Single Cobalt Atoms Induced Molecular O₂ Activation for Enhanced Photocatalytic Biomass Upgrading on ZnIn₂S₄ Nanosheets

Abstract

Photocatalytic selective biomass aerobic oxidation to high-value products is promising for meeting carbon-neutral demand; however, great challenges remain in the lack of appropriate active sites for molecular O 2 activation and understanding their role at the atomic scale to reveal the underlying mechanism. Herein, we report that a rational decoration of ultralow-amount (0.08 wt %) Co single atoms on ZnIn 2 S 4 nanosheets (Co 1 /ZIS) enables both high activity and selectivity for photocatalytic 5-hydroxymethylfurfural (HMF) oxidation to the high-value 2,5-dicarbonylfuran (DFF) product. Under visible light irradiation in an air atmosphere, Co 1 /ZIS exhibits 98.6% conversion of HMF that outperforms pristine ZIS by two times, along with 92.4% selectivity of DFF. Uncovered by combined experimental results and computational calculations, the introduction of Co single atoms not only facilitates the transfer of photogenerated carriers but also provides active sites to promote the adsorption/activation of O 2 to generate reactive oxygen species of • O 2 − and 1 O 2 , thereby leading to its superior photocatalytic performance to the pristine ZIS counterpart.

Binder-Free Carbon Nitride Panels for Continuous-Flow Photocatalysis

“…It should be noted that using CN panels in continuous-flow conditions, we achieved high HMF conversion rate (1185 μmol h –1 g –1 ), which is among the state-of-the-art heterogeneous photocatalysts (Figure c and Table S5). − Postoperational characterization studies emphasize the structural and chemical stability of the panel after a continuous operation for 24 h (Figures S28 and S29). This stability and the high HMF conversion in pure water motivate the adaptation of continuous-flow photochemistry to oxidation reactions of more challenging biomass substrates (e.g., lignin, cellulose, and glycerol).…”

Tailoring the d-band center enables La doped ZnIn2S4 to be active for boosting photocatalytic activation of oxygen and degradation of antibiotics in wastewater

“…Various modification methods, such as heterostructure design, defect engineering, co-catalyst loading, and element doping, have been employed for fine-tuning of the coordination environment and electron distribution of active sites in ZIS. 26–29 Previous studies have demonstrated that the d orbital configuration significantly impacts the electronic properties of transition metal cations on the catalyst surface, as well as their interaction with reactants. 30–33 Norskov et al introduced the d-band center theory, which has been proven to be an indicator of the binding strength of key intermediates in catalytic reactions.…”