A Full‐Spectrum‐Responsive MOF‐on‐MOF Heterojunction Photocatalyst for Concurrent Nitrate Reduction and Biomass Oxidation

ABSTRACT Photocatalytic nitrate reduction reaction (PNitRR) offers a sustainable route for ammonia (NH 3 ) synthesis and wastewater treatment. The insufficient utilization of near‐infrared (NIR) light and sluggish reaction kinetics of coupled water oxidation result in unsatisfactory performance. Herein, a conductive metal organic framework ( c MOF)‐on‐ c MOF S‐scheme heterojunction is reported as an efficient full‐spectrum photocatalyst for driving an innovative hybrid system of PNitRR to NH 3 and photocatalytic 5‐hydroxymethylfurfural oxidation reaction (PHMFOR) to 2, 5‐furandicarboxylic acid (FDCA). The integration of Co‐ c MOF and Ni‐ c MOF with dual NIR‐response features and well‐matched band structures into an S‐scheme heterojunction enables sufficient light utilization and efficient charge separation. Moreover, the formation of interfacial Ni‐Co dual sites with modulated electronic structures accounts for PNitRR and PHMFOR, respectively, with enhanced activity and selectivity. The designed c MOF‐on‐ c MOF S‐scheme heterojunction photocatalyst exhibits production rates of 4677.5 and 5932.5 µmol g cat −1 h −1 with apparent quantum yields of 13.3% and 13.1% at 500 nm for NH 3 and FDCA production, respectively. This work opens new avenues for the development of advanced photocatalysts and integrated photocatalytic systems to produce valuable chemicals.