Non-graphitized carbon/Cu₂O/Cu⁰ nanohybrids with improved stability and enhanced photocatalytic H₂ production

Cu₂O is a highly potent photocatalyst, however photocorrosion stands as a key obstacle for its stability in photocatalytic technologies. Herein, we show that nanohybrids of Cu₂O/Cu⁰ nanoparticles interfaced with non-graphitized carbon (nGC) constitute a novel synthesis route towards stable Cu-photocatalysts with minimized photocorrosion. Using a Flame Spray Pyrolysis (FSP) process that allows synthesis of anoxic-Cu phases, we have developed in one-step a library of Cu₂O/Cu⁰ nanocatalysts interfaced with nGC, optimized for enhanced photocatalytic H₂ production from H₂O. Co-optimization of the nGC and the Cu₂O/Cu⁰ ratio is shown to be a key strategy for high H₂ production, > 4700 μmoles g^-1 h^-1 plus enhanced stability against photocorrosion, and onset potential of 0.234 V vs. RHE. After 4 repetitive reuses the catalyst is shown to lose less than 5% of its photocatalytic efficiency, while photocorrosion was < 6%. In contrast, interfacing of Cu₂O/Cu⁰ with graphitized-C is not as efficient. Raman, FT-IR and TGA data are analyzed to explain the undelaying structural functional mechanisms where the tight interfacing of nGC with the Cu₂O/Cu⁰ nanophases is the preferred configuration. The present findings can be useful for wider technological goals that demand low-cost engineering, high stability Cu-nanodevices, prepared with industrially scalable process.