Plasma-induced defective TiO2- x with oxygen vacancies: A high-active and robust bifunctional catalyst toward H2O2 electrosynthesis

Achieving high selectivity and production efficiency simultaneously in electrocatalytic H2O2 production to replace the anthraquinone process via two-electron ( 2e (-)) oxygen reduction reaction (ORR) and 2e(-) water oxidation reaction ( WOR) is a long-sought-after goal. However, sluggish kinetics and intrinsically unfavored thermodynamics make the electrochemical method still far from practical implementation. Herein, we experimentally demonstrate a high-efficiency two-side H2O2 generation system (WOR//ORR coupling cell) basedon an active andstablebifunctional plasma-induced defective TiO2- x nanocatalyst that exhibits dramatically boosted activity/ selectivity for both 2e(-) ORR and 2e(-) WOR. Such a WOR-ORR coupling strategy enables the H2O2-producing cell to provide an ultrahigh H2O2 yield rate of similar to 20 mmol L-1 h(-1) and a remarkable cell Faradaic efficiency of up to 134%. In situ Raman spectroscopy results and density functional theory calculations together uncover that oxygen vacancies located at the inner atomic layer and surface distortion are responsible for enhanced 2e (-) ORR and 2e(-) WOR performance, respectively.Achieving high selectivity and production efficiency simultaneously in electrocatalytic H2O2 production to replace the anthraquinone process via two-electron ( 2e (-)) oxygen reduction reaction (ORR) and 2e(-) water oxidation reaction ( WOR) is a long-sought-after goal. However, sluggish kinetics and intrinsically unfavored thermodynamics make the electrochemical method still far from practical implementation. Herein, we experimentally demonstrate a high-efficiency two-side H2O2 generation system (WOR//ORR coupling cell) basedon an active andstablebifunctional plasma-induced defective TiO2- x nanocatalyst that exhibits dramatically boosted activity/ selectivity for both 2e(-) ORR and 2e(-) WOR. Such a WOR-ORR coupling strategy enables the H2O2-producing cell to provide an ultrahigh H2O2 yield rate of similar to 20 mmol L-1 h(-1) and a remarkable cell Faradaic efficiency of up to 134%. In situ Raman spectroscopy results and density functional theory calculations together uncover that oxygen vacancies located at the inner atomic layer and surface distortion are responsible for enhanced 2e (-) ORR and 2e(-) WOR performance, respectively.Achieving high selectivity and production efficiency simultaneously in electrocatalytic H2O2 production to replace the anthraquinone process via two-electron ( 2e (-)) oxygen reduction reaction (ORR) and 2e(-) water oxidation reaction ( WOR) is a long-sought-after goal. However, sluggish kinetics and intrinsically unfavored thermodynamics make the electrochemical method still far from practical implementation. Herein, we experimentally demonstrate a high-efficiency two-side H2O2 generation system (WOR//ORR coupling cell) basedon an active andstablebifunctional plasma-induced defective TiO2- x nanocatalyst that exhibits dramatically boosted activity/ selectivity for both 2e(-) ORR and 2e(-) WOR. Such a WOR-ORR coupling strategy enables the H2O2-producing cell to provide an ultrahigh H2O2 yield rate of similar to 20 mmol L-1 h(-1) and a remarkable cell Faradaic efficiency of up to 134%. In situ Raman spectroscopy results and density functional theory calculations together uncover that oxygen vacancies located at the inner atomic layer and surface distortion are responsible for enhanced 2e (-) ORR and 2e(-) WOR performance, respectively.

Automated summary

Achieving high selectivity and production efficiency in electrocatalytic H2O2 production has been a long-sought goal. This study demonstrates a high-efficiency H2O2 generation system based on a plasma-induced defective TiO2-x nanocatalyst, enabling ultrahigh H2O2 yield rate and remarkable cell Faradaic efficiency through a WOR-ORR coupling strategy. The results suggest that oxygen vacancies and surface distortions play key roles in enhancing ORR and WOR performance.