Enhanced electrochemical hydrogen peroxide productionfrom surface state modified mesoporous tin oxide catalysts

Electrochemical hydrogen peroxide (H2O2) production via the two-electronoxygen reduction reaction (ORR) has received much consideration as a substi-tute to the well-known industrial anthraquinone method. The present chal-lenge in this area is developing appropriate cost-efficient materials withexcellent electrocatalytic properties, durability, and product selectivity. Thisstudy examined electrocatalytic performance and selectivity toward H2O2pro-duction of mesoporous SnO2(meso-SnO2) electrodes prepared using a tunablehydrothermal process. After evaluating the effects of different NaCl concentra-tions and annealing conditions in the hydrothermal method, an electrode wasdeveloped with a significantly improved H2O2production rate than the pris-tine material. Vacuum annealing led to materials with more surface defects.Meso-SnO2annealed under vacuum exhibits distinctive electrochemical prop-erties of two well-separated 2e O2reduction peaks to produce H2O2as themain product compared tomeso-SnO2annealed in air. Most importantly, theintroduction of surface oxygen vacancies into themeso-SnO2crystal structurewas determined to be a prominent approach to enhance its ORR performancein producing H2O2, showing great selectivity of above 85% at an onset potentialof 0.6 VRHE. The vacancy-richmeso-SnO2reveals enhanced electrocatalyticperformance with ORR peak potential to be 0.6 VRHE,and the number of elec-tron transfer numbers is 2.5, but greater durability in alkaline solutions. Thus,this work presents an innovative route for designing, synthesizing, and mecha-nistic examining enhanced SnO2-based catalytic materials for H2O2production.