Constructing Strongly Coupled g‑C3N4/Hf‑MOF Heterojunctions for Efficient and Highly Selective Photocatalytic CO2 Reduction to Methanol

Through a simple hydrothermal strategy, a strongly coupled g‑C 3 N 4 /Hf‑MOF heterojunction (CN/HUN) was successfully prepared, achieving efficient and selective photocatalytic CO 2 reduction to methanol without sacrificial agents. After reacting for 3 hours under simulated sunlight conditions without a sacrificial agent, the optimized CN/HUN 7 catalyst achieved a cumulative methanol yield of 520.48 μmol g -1 and a selectivity of 83%. Systematic characterization indicates that the strong interfacial interactions and electronic coupling between g-C 3 N 4 and Hf-MOF effectively accelerate charge separation, suppress carrier recombination, and significantly reduce charge transfer resistance. Furthermore, the Hf-MOF forms a Z-type heterojunction structure with g-C 3 N 4 , thereby enabling directed electron transfer. While electrons in the conduction band (CB) of the Hf-MOF are transferred to the valence band (VB) of g-C 3 N 4 , the unsaturated Hf 4+ sites may promote CO 2 adsorption and activation through Lewis acid-base interactions and are expected to stabilize key intermediates during the CO 2 reduction process, thereby enhancing the performance of CO 2 reduction to methanol. We demonstrate a viable route to construct tightly integrated MOF heterojunctions for high-performance photocatalytic CO 2 reduction to fuels. Download: Download high-res image (236KB) Download: Download full-size image