Precisely anchoring Ni-doped cobalt phosphide nanoparticles on phosphatized carbon nitride for efficient photocatalytic water splitting

Abstract

Photocatalytic water splitting into hydrogen (H2) fuel or hydrogen peroxide (H2O2) chemicals has been considered as an ideal approach for converting solar energy into chemical energy. However, simultaneous production for these two valuable chemicals was always accompanied by the unsatisfactory catalytic productivity. Herein, we have employed the absorption-phosphidation strategy for precisely anchoring Ni-doped cobalt phosphide (CoP) nanoparticles (∼4 nm) on phosphatized carbon nitride (PCN) nanosheet. Without adding any sacrificial reagents, the photocatalyst exhibited excellent H2 evolution activities (248 μmol·g−1) and H2O2 generation (894 μmol·g−1) at 2 h, one of the highest activities among the previously reported carbon nitride-based catalysts. Comprehensive characterizations revealed that atomic-scale doped Ni element within CoP nanoparticles significantly accelerated surface catalytic reaction kinetics, which serve as the active centers for H2 and H2O2 evolution through reduction reaction. The PCN nanosheets with the increased electric conductivity and the decreased band gap energy could effectively promote photo-generated charge separation and transfer. Moreover, the Co-N coordination effect between PCN and Ni-doped CoP cocatalysts, could also accelerate the interfacial electron transfer. Synergizing the PCN nanosheet and intimately anchored Ni-CoP nanoparticles remarkably promoted the photocatalytic productivity and stability for simultaneous H2 and H2O2 production.