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From the viewpoints of energy and the environment, NH3 splitting into N2 and H2 is an important challenge in chemistry, and we have found that BiVO4 is a highly promising base photoanode material for it. Semiconductor films (TiO2 and BiVO4) were formed on a fluorine-doped tin oxide (FTO) electrode, and three-electrode photoelectrochemical (PEC) cells using them as the photoanodes were fabricated. The photocurrent in the TiO2/FTO photoanode cell is saturated at ∼0.1 mA cm−2 in the range of electrode potential (E) more positive than +0.3 V vs. the standard hydrogen electrode (SHE) in an electrolyte solution containing NH3 (pH 11) under illumination of simulated sunlight (AM 1.5, 100 mW cm−2, one sun). In contrast, the photocurrent in the BiVO4/FTO photoanode cell increases with increasing anodic polarization to reach 1.78 mA cm−2 at E = +1 V vs. SHE. This PEC cell produces H2 from NH3 with a selectivity of 92% under the same irradiation conditions, and the incident photon-to-current conversion efficiency reaches 11.7% at a wavelength of excitation light = 365 nm. Provision of an SnO2 interlayer between the BiVO4 and FTO films effectively suppresses the recombination at the interface to enhance the photocurrent under weak anodic polarization at E < +0.5 V vs. SHE.

Correction for ‘Rational design and recent advancements of additives engineering in ASnI3 tin-based perovskite solar cells: insights from experiments and computational’ by Maria Ulfa et al., Sustainable Energy Fuels, 2023, 7, 5198–5223, http://doi.org/10.1039/D3SE00571B.

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Steam reforming of methane (SRM) is one of the most useful techniques for methane (CH4) conversion because of the large hydrogen yield per CH4 molecule. However, this process is not commercially viable due to the high reaction temperature and associated energy costs. To decrease the SRM reaction temperature, the introduction of photochemical energy has been proposed; however, the charge recombination of photo-generated carriers must be suppressed to achieve higher activity. Here, TiO2 photocatalysts with a hollow sphere structure are synthesized and loaded with spatially separated co-catalysts to achieve high charge separation in an attempt to improve SRM efficiency. The highest SRM activity is observed for hollow-sphere structured TiO2 with Pt and Rh2O3 co-catalysts selectively deposited on the inner and outer TiO2 surfaces, respectively. In situ electron spin resonance and photo-luminescence measurements clearly demonstrate that photo-excited electrons and holes are trapped at Pt and Rh2O3 sites, respectively, of Rh/hollow TiO2/Pt, resulting in efficient charge separation and increased SRM activity. Taken together, these findings support our hypothesis that the spatial separation and heterogeneous loading of co-catalysts is a promising design strategy for photocatalytic methane conversion reactions.

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After decades of effort, the performance of low-cost transition metal–nitrogen–carbon (M–N–C) catalysts has been significantly improved, positioning them as promising catalysts for the oxygen reduction reaction in proton-exchange-membrane fuel cells (PEMFCs). Despite this progress, compared to traditional commercial Pt/C catalysts, the practical application of M–N–C catalysts in PEMFCs is hindered by their inferior performance in acidic environments. In this perspective, we first summarize the current status of M–N–C catalysts in terms of activity and stability, and compare their performance with that of Pt/C catalysts. Then we discuss the fundamental research challenges associated with M–N–C catalysts, which are primarily related to (i) conducting basic research with tests exclusively using oversimplified aqueous electrolytes that limits exploration in practical fuel cell environments; (ii) lacking operando characterization methods under fuel cell working conditions; and (iii) the complexity of catalyst structures and fuel cell operating environments causing difficulty in M–N–C catalyst research. Lastly, we propose key advances that need to be made in the future to address these fundamental challenges, including the rational design of fit-for-purpose catalysts based on more cost-effective and efficient modelling, preparing model/quasi-model catalysts with defined and controllable structures, and developing operando characterization techniques for PEMFCs. By combined study using model/quasi-model catalysts, operando characterization methods and atomistic modeling, we can deeply understand the “structure-performance” relationship of the catalysts at various scales and develop next generation M–N–C catalysts that can meet the increased demand for PEMFCs.

This study reports a promising and innovative approach for electrochemical green H2 generation using distillery industry wastewater. We employed solvothermally derived Ni2Se3 nanoparticles with a particle size of ∼50 nm as the anode catalyst material to effectively oxidise the acetic acid present in the distillery wastewater. The utilisation of a Ni2Se3 nanoparticle-coated stainless steel electrode significantly enhanced the current density (282 mA cm−2) in the electrochemical cell compared to the pristine SS (stainless steel) electrode (146 mA cm−2) at 2 V RHE. Also, the distillery wastewater electrolyte based cell exhibits higher current density compared to conventional freshwater (i.e., NaOH-based) electrolyte. The distillery wastewater electrolyte demonstrated remarkable H2 gas evolution (∼15 mL h−1 cm−2), showcasing its potential for sustainable H2 generation. However, it was observed that the aggressive bubbling effect at the cathode led to a lower H2 evolution reaction activity when compared to the freshwater-based electrolyte, which displayed a H2 production rate of ∼22 mL h−1 cm−2. These findings underscore the potential of employing Ni2Se3 as an effective oxidation catalyst in the production of H2 gas from pre-treated brewery wastewater H2 gas. The utilisation of Ni2Se3 nanoscale water oxidation catalysts in this context opens up new possibilities for both wastewater treatment and H2 production, paving the way for a more sustainable and resource-efficient future.

Effects of co-doping of aluminum (Al), scandium (Sc), and magnesium (Mg) into SrTiO3 particles by a high temperature (1200 °C) flux treatment in a molten SrCl2 on the structural properties and photocatalytic activities for overall water splitting were investigated. Isotropically-rounded polygonal-shaped particles of almost phase-pure SrTiO3 crystals were obtained from SrTiO3 particles co-doped with Al and Sc (SrTiO3:Al,Sc) and Al and Mg (SrTiO3:Al,Mg), whereas, the cubic-shaped particles having specific nanosized steps on the edge of each particle were obtained by co-doping with Sc and Mg (SrTiO3:Sc,Mg). Apparent quantum yields (AQYs) for overall water splitting at a band edge region (365 nm) were examined using these SrTiO3 samples loaded with Rh/Cr2O3 and CoOOH cocatalyst nanoparticles (for H2 and O2 evolution, respectively), and it reached the highest (66%) when the photocatalyst based on SrTiO3:Sc,Mg was used. The best photocatalytic performance obtained over the photocatalyst is attributed to the achievement of the separation of reaction sites for reduction and oxidation of water, i.e., the former reaction occurred on the Rh/Cr2O3 cocatalyst selectively deposited on the flat {100} facets of the SrTiO3:Sc,Mg particle, whereas the later O2 evolution occurred on the CoOOH cocatalyst that was only deposited on the nanosized step part on the particle.

In this work, a self-supported electrode based on porous carbon sheets was prepared by a high-temperature calcination of a phenolic resin using hexamethylenetetramine as a nitrogen source and curing agent and KCl salt templates as pore-forming agents, and it was tested for the electrocatalytic reduction of CO2 to syngas. The effects of the KCl addition amount on the morphology, pore structure, and electrocatalytic activity of the self-supported electrodes for CO2 reduction were also investigated. The results indicated that the amount of KCl has significant impacts on the morphology, pore structure, N-containing species and electrochemical properties of carbon materials. Specifically, the electrode with a 40% KCl content had a maximum surface area of 71.29 m2 g−1, a medium pore size of 22.47 nm, and a CO Faraday efficiency of 48% at −1.2 V vs. Ag/AgCl with a current density of 10 mA cm−2. Specifically, the H2/CO molar ratio could be adjusted from 1.09 to 3.38 by changing the applied potential. The superior electrocatalytic performance is attributed to the high strength, large specific surface area, and suitable pore structure of the material. The high strength ensures a stable and sustainable reaction, the large specific surface area fully exposes the reactive active sites, and the suitable pore structure promotes the effective adsorption of reactant CO2. The porous carbon sheet self-supported electrode designed in this experiment overcomes the disadvantages of expensive and short-lived precious metal catalysts and the need for adhesives in powder catalysts, providing a new strategy for the electrocatalytic conversion of CO2 into ideal products at low potentials.

A kind of novel Z-scheme BiOBr/BiVO4 composite film has been successfully synthesized on a Bi plate by the electrochemical ion-exchange method using BiOBr nanosheets as the template and NH4VO3 as the ion-exchange source. Under simulated sunlight irradiation, the BiOBr/BiVO4 composite film exhibits excellent photocatalytic CO2 reduction activity to CO with a production rate of 95.27 μmol g−1 h−1, 1.62 and 1.39 times higher than that of pure BiVO4 and BiOBr, respectively, which should be attributed to the significantly enhanced separation of photogenerated carriers owing to the formation of a Z-scheme heterojunction structure between BiOBr and BiVO4 interfaces. The Z-type transfer path of photoinduced electrons in BiOBr/BiVO4 composite films is confirmed through the calculated work functions of BiOBr and BiVO4 using density functional theory (DFT). This work should provide new important insights into the immobilization of highly efficient Bi-based photocatalysts and their application in the photocatalytic CO2 green conversion into high value-added chemicals or fuels.

Coulombic efficiency (CE) is widely considered to be an important parameter for indicating the loss of reversibility of lithium, which can be used to reflect battery performance and safety to predict the lifespan in Li-ion battery research. However, the quantifiable relationship between CE and lifespan, as well as its application in lifespan prediction for real-world electrical vehicles (EV), are not fully understood. In this paper, the battery cycle degradation test is performed, which explores the close relationship between the CE and the cycle life through the study of an experimental cell with graphite anodes (AG) coated with different proportions of pitch-based carbon (PbC), indicating that a high CE is associated with a long battery life. Furthermore, the CE evolution is explored through cycling experiments of the standard cell under imitated real-world EV working conditions and the logarithmic relation with upper and lower branches between the CE and cycle number is constructed. Based on this relationship, a quantitative lifespan prediction method for EVs is proposed. It was found that the failure behavior of the degradation trend could be identified through the mass EVs operating data by using this method, and the false alarm for normal EVs is low, at only about 2% by cycle number, indicating that CE in EVs reflects the health status of lifespan (HSoL) of battery. Therefore, the detection method is helpful for predicting the cycle life and offers an early failure warning for battery management systems.

Biomass-derived chemicals, such as hydroxymethylfurfural (HMF), have the potential to supplement other petroleum-derived products. Several catalysts have been reported in the literature for producing HMF from fructose, glucose, and starch; however, challenges like low catalyst activity, deactivation, or difficult recovery have been encountered. Here, we report a series of polystyrene-based catalysts with simultaneous Brønsted and Lewis acidity and the advantages of both homogeneous and heterogeneous catalysis: soluble in water and easy to recover and reuse. For the first time, we show that these novel catalysts can be prepared under atmospheric conditions without the need for an inert atmosphere or costly anhydrous solvents, which is an advantage from an environmental and economic point of view. Additionally, we report that these catalysts can carry out the one-pot synthesis of HMF from potato starch, which involves the hydrolysis of starch, isomerization of glucose to fructose, and dehydration of fructose to HMF.

Hierarchical hybrid heterostructures are promising for efficient and sustainable electrocatalysts due to their various morphologies and outstanding electrochemical properties. Herein, heterostructured CuxO@NiCoS nanoarrays were in situ constructed on copper foam (denoted as CuxO@NiCoS/CF) and used as electrocatalysts for alkaline overall water splitting. Benefiting from the hierarchical hybrid heterostructure that exposes abundant active sites and the synergistic effect between CuxO and NiCoS, CuxO@NiCoS/CF shows better electrocatalytic performance than single-component electrocatalysts (CuxO/CF and NiCoS/CF). The influence of the initial metal source ratio (Ni/Co) during the electrodeposition on electrocatalytic performance was further investigated. Impressively, the optimized CuxO@NiCoS-1/CF exhibits a small overpotential of 110 mV at 10 mA cm−2 for the hydrogen evolution reaction (HER) and 313 mV at 30 mA cm−2 for the oxygen evolution reaction (OER). Moreover, CuxO@NiCoS-1/CF as bifunctional electrocatalysts reach a current density of 30 mA cm−2 at a low cell voltage of 1.79 V and display remarkable electrocatalytic durability in an alkaline solution. This work can provide a new idea for designing and preparing novel non-noble metal electrocatalysts with the benefit of structural diversity.

The coupling system of a Proton Exchange Membrane Fuel Cell (PEMFC) and Metal Hydride (MH) canister was investigated, employing a double spiral structure to redirect waste heat from the PEMFC to the MH. The remaining heat was harnessed for seawater desalination via a Multi-Stage Flash Desalination (MSF) apparatus. By analyzing the operation of the PEMFC at various power points and dividing the hydrogen release process into stages A, B, and C, we investigate the time evolution law of each parameter of the MH bed. We evaluate the effects of the PEMFC operating parameters and the double spiral geometry parameters on the system's stable operation duration. The results reveal that the current density of the PEMFC significantly affected the system performance, while its operating temperature exerted a limited impact; the system exhibits greater suitability for long-term, low-power operation mode. Furthermore, the system's efficiency can reach up to 81.7%, with a stable working time of 6790 seconds. Considering the heat exchange in the MH canister, the double spiral heat exchanger's position occupancy problem, and the double-tube synergistic effect together, the MH is divided into α, β, and γ zones, and the heat exchanger geometrical parameters are optimized for the study. It is recommended to employ a tube diameter of 0.015 m and a coil spacing of 0.030 m for the heat exchanger.

In this study, quasi-solid polymer electrolytes incorporating an ionic liquid (ILQSEs) fabricated in different organic solvents via a thermally-initiated polymerization strategy were investigated for flexible supercapacitors (SCs). It was found that low-viscous acetonitrile (AN) with a strongly-polar nitrile group was remained in the polymer matrix, which favored a higher ionic conductivity, wider electrochemical window, and better thermal stability of the ILQSE compared to its propylene carbonate (PC) counterpart. Moreover, the in situ polymerized quasi-solid electrolyte achieved close contact with the porous carbon electrode, accompanied by the favorable permeation of the IL into the electrode for enhancing the ion-transport kinetics and interface stability. Consequently, the as-assembled SC with the AN-based ILQSE delivered a high specific energy and specific power, excellent cycle stability, and reliable safety.

In the context of sustainable residual biomass management, this work explores the pyrolysis process of residual biomass using a bench-scale fixed bed reactor. The main focus is to comprehensively analyze the effects of diverse forest and agroforestry biomass, pyrolysis temperature (350, 450 and 550 °C) and heating rate (2, 10 and 30 °C min−1) on the yield of the products biochar, bio-oil and permanent gas, and on the composition of biochar and permanent gas. This analysis provides a valuable collection of insights to support the advancement of pyrolysis projects and their expansion into industrial production, facilitating the creation of versatile products. The study showed that the biochar, bio-oil and permanent gas yields were between 0.22 and 0.47, 0.26 and 0.59 and 0.17 and 0.41 kg kg−1 dry biomass, respectively. The pyrolysis of olive pomace has the maximum biochar yield, that of eucalyptus sawdust has the maximum bio-oil yield, and that of giant reed has the maximum permanent gas yield. The increased temperature led to a decreased biochar yield and an increased bio-oil yield. The increased heating rate led to a decreased biochar yield and an increased bio-oil yield. Biochar has a carbon content above 0.7 kg kg−1 dry ash free, with an LHV between 24.2 and 30.5 MJ kg−1 dry biochar, suggesting potential for soil enrichment and the energy vector. Permanent gas has an LHV between 5.4 and 9.7 MJ Nm−3, and seems useful as a thermal energy source to support the pyrolysis process.

The absorption and desorption behaviours of ammonia (NH3) on bis(fluorosulfonyl)amide (FSA) salts were investigated using the pressure-swing method. The effects of the cation species and temperature of the four types of FSA single salts (Li[FSA], Na[FSA], K[FSA], and Ca[FSA]2) and (Na, K)[FSA] eutectic melt on the NH3 absorption behaviour were evaluated. FSA salts exhibited large NH3 storage capacities and the NH3 absorption behaviour was affected by the different FSA salt cation species. The NH3 storage capacity increased with decreasing temperature. Although the alkaline metal FSA salts were liquefied by NH3 absorption at 300 K, Ca[FSA]2 remained solid after NH3 absorption at 300 K. Additionally, K[FSA] absorbed a lower amount of NH3 than at 300 K and remained in the solid state after NH3 absorption at 323 K. These results suggest that NH3 molecules were dissolved in the FSA salts, and eutectic compounds were formed by NH3 absorption on the FSA salts. After NH3 absorption, the salts were found to be composed of ammonium (NH4+) cations and amide (NH2−) and imide (NH2−) anions.

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