An in situ derived MOF@In 2 S 3 heterojunction stabilizes Co(II)-salicylaldimine for efficient photocatalytic formic acid dehydrogenation.

We report here the hierarchical construction of a molecular Co(II)-salicylaldimine catalyst and an in situ derived In 2 S 3 semiconductor in a MOF@In 2 S 3 heterojunction through sequentially controllable in situ etching and post-synthetic modification for photocatalytic hydrogen production from formic acid. The enhanced catalyst stability and facilitated charge carrier mobility between the In 2 S 3 photosensitizers and Co catalyst realize a superior H 2 production rate of 18 746 μmol g -1 h -1 (selectivity > 99.9%) with a turnover number (TON) of up to 6146 in 24 h (apparent quantum efficiency of 3.8% at 420 nm), indicating a 165-fold enhancement over that of the pristine MOF. This work highlights a powerful strategy for synergistic Earth-abundant metal-based MOF photocatalysis in promoting H 2 production from FA.