A Synergistic Photocatalysis–Electrocatalysis System for Efficient Hydrogen Generation and Energy‐Saving Benzylamine Oxidative Upgrading

Photocatalytic hydrogen iodide (HI) splitting represents a promising tactic for H₂ generation, but the light-shielding effect induced by the generated I₃ ^- greatly impedes subsequent reactions. A critical challenge in this field lies in achieving the timely reduction of I₃ ^- while avoiding the use of additional sacrificial agents, such as H₃PO₂. Herein, we develop a synergistic photocatalysis-electrocatalysis system to address this challenge and achieve efficient H₂ generation and benzylamine oxidative upgrading. The photocatalytic component features a Re_0.5Mo_0.5S₂ cocatalyst-modified MAPbI₃ with efficient charge separation and ample active sites, achieving a remarkable H₂ generation of 875.4 µmol within 4 h through HI splitting. The subsequent electrocatalytic module can operate at a low potential (only 0.44 V to reach 10 mA cm^-2) to reduce the generated I₃ ^- and oxidize benzylamine to value-added chemicals. After the electrolysis, the regenerated HI solution can be recycled for subsequent photocatalytic H₂ generation. The synergistic system establishes a sustainable catalytic cycle mediated by I^-/I₃ ^- redox couples, enabling continuous photocatalytic H₂ generation from HI splitting and energy-saving electrocatalytic benzylamine oxidative upgrading.