Cu/Biochar Bifunctional Catalytic Removal of COS and H 2 S:H 2 O Dissociation and CuO Anchoring Enhanced by Pyridine N.

Economic and environmentally friendly strategies are needed to promote the bifunctional catalytic removal of carbonyl sulfide (COS) by hydrolysis and hydrogen sulfide (H 2 S) by oxidation. N doping is considered to be an effective strategy, but the essential and intrinsic role of N dopants in catalysts is still not well understood. Herein, the conjugation of urea and biochar during Cu/biochar annealing produced pyridine N, which increased the combined COS/H 2 S capacity of the catalyst from 260.7 to 374.8 mg·g -1 and enhanced the turnover frequency of H 2 S from 2.50 × 10 -4 to 5.35 × 10 -4 s -1 . The nucleophilic nature of pyridine N enhances the moderate basic sites of the catalyst, enabling the attack of protons and strong H 2 O dissociation. Moreover, pyridine N also forms cavity sites that anchor CuO, improving Cu dispersion and generating more reactive oxygen species. By providing original insight into the pyridine N-induced bifunctional catalytic removal of COS/H 2 S in a slightly oxygenated and humid atmosphere, this study offers valuable guidance for further C═S and C-S bond-breaking in the degradation of sulfur-containing pollutants.