A facile and effective solvent-switched in situ confinement approach (SSISCA) has been developed to immobilize ultrafine and clean Pd NPs of ∼1.75 nm into a nanoporous carbon support. The Pd NPs in situ confined within the carbon nanopores possess high catalytic activity and selectivity for hydrogen evolution from formic acid with a record-high TOF of 9110 h−1 at 60 °C.
