In-situ decoration of unsaturated Cu sites on Cu2O photocathode for boosting nitrogen reduction reaction

Photoelectrochemical N 2 reduction reaction (PEC NRR) into chemical energy source is a promising technique for solving environmental challenges and the energy crisis, which depends on the exploration of p-type photocathodes. Cu 2 O is a p-type semiconductor, which can be applied as a photocathode for PEC NRR. However, the adsorption and activation ability of N 2 over the pristine Cu 2 O is still not ideal, causing the overall efficiency far below the theoretical value. In this work, we first proposed a feasible strategy to in-situ modify the surface of Cu 2 O with Cu-MOF, and the Cu-MOF/Cu 2 O heterostructure exhibited the significantly boosted NH 3 production rate (7.16 mmol/m 2 /h). The ultra-thin Cu-MOF film takes a nature of porous structure and unsaturated Cu sites, contributing to a favorable interface environment for the adsorption and activation of N 2 . The N 2 temperature programmed desorption and contrast photocurrent curves revealed the desirable selectivity for PEC NRR, and the isotope NMR further confirmed the accuracy of NH 3 evolution process. Therefore, the organic–inorganic hybrid systems built from Cu-MOF and Cu 2 O would offer a new insight for establishing the efficient PEC NRR system.