Defect engineering via ternary nonmetal doping boosts the catalytic activity of ZIF-derived carbon-based metal-free catalysts for photovoltaics and water splitting

The precise adjustment of the electronic structure of catalysts is an effective but difficult strategy for enhancing their catalytic performance. In this work, a defect engineering strategy was adopted to optimize the electronic structure of zeolitic imidazole zinc framework (ZIF)-derived in-situ nitrogen-doped carbon (N-C) via doping with nonmetal atoms (B and P/S). The doped nonmetal atoms altered the regular geometric construction of the catalyst and redistributed the electrons on the substrate, thus modifying the adsorption properties and catalytic ability of the catalyst. Benefitting from the modified electronic structure, enhanced structural defects, and synergistic effects among the different atoms, the N, B, and P/S co-doped carbon catalysts (BPN???C and BSN-C) exhibited enhanced catalytic activity. The best results were observed for BSN-C, which exhibited excellent catalytic activity for triiodide reduction reaction (IRR) in a photovoltaic device with an efficiency of 8.23%, superior to that of Pt (7.20%). BSN-C also produced a low overpotential of 129.7 mV at the current density of 10 mA cm-2 in an alkaline hydrogen evolution reaction (HER). BPN-C and BSN-C displayed remarkable stability in the IRR and HER. This work presents a promising strategy for designing superior carbon-based metal-free catalysts via multivariate doping with non-metal heteroatoms for new energy applications.