Manifolding active sites and in situ/operando electrochemical-Raman spectroscopic studies of single-metal nanoparticle-decorated CuO nanorods in furfural biomass valorization to H2 and 2-furoic acid

Here, CuO nanorods fabricated via pulsed laser ablation in liquids were decorated with Ir, Pd, and Ru NPs (loading ∼7 wt%) through pulsed laser irradiation in the liquids process. The resulting NPs-decorated CuO nanorods were characterized spectroscopically and employed as multifunctional electrocatalysts in OER, HER, and the furfural oxidation reactions (FOR). Ir–CuO nanorods afford the lowest overpotential of ∼345 mV (HER) and 414 mV (OER) at 10 mA cm−2, provide the highest 2-furoic acid yield (∼10.85 mM) with 64.9% selectivity, and the best Faradaic efficiency ∼72.7% in 2 h of FOR at 1.58 V (vs. RHE). In situ electrochemical-Raman analysis of the Ir–CuO detects the formation of the crucial intermediates, such as Cu(III)-oxide, Cu(OH)2, and Irx(OH)y, on the electrode–electrolyte surface, which act as a promoter for HER and OER. The Ir–CuO || Ir–CuO in a coupled HER and FOR-electrolyzer operates at ∼200 mV lower voltage, compared with the conventional electrolyzer and embodies the dual advantage of energy-saving H2 and 2-furoic acid production.