3‐Hydroxythiophenol‐Formaldehyde Resin Microspheres Modulated by Sulfhydryl Groups for Highly Efficient Photocatalytic Synthesis of H2O2

Abstract

AbstractResorcinol‐formaldehyde (RF) resin represents a promising visible‐light responding photocatalyst for oxygen reduction reaction (ORR) toward H2O2 production. However, its photocatalytic ORR activity toward H2O2 generation is still unsatisfied for practical application. Herein, 3‐hydroxythiophenol‐formaldehyde (3‐HTPF) resin microspheres synthesized through polycondensation reaction between 3‐HTP and formaldehyde at room temperature and subsequent hydrothermal treatment exhibit enhanced photocatalytic ORR activity is reported. The experimental results show that the partial substitution of hydroxy group (─OH) by sulfhydryl one (─SH) through using 3‐HTP to replace resorcinol could slow the rates of nucleation and growth of the resin particles and lead to strongly π‐stacked architecture in 3‐HTPF. The introduction of ─SH group can also improve adsorption ability of 3‐HTPF to O2 molecules and enhance ORR catalytic activity of the photocatalysts. Stronger built‐in electric field, better adsorption ability to O2 molecules, and increased surface catalytic activity collectively boost photocatalytic activity of 3‐HTPF microspheres. As a result, H2O2 production rate of 2010 µm h−1 is achieved over 3‐HTPF microspheres at 273 K, which is 3.4 times larger than that obtained using RF submicrospheres (591 µm h−1). The rational substituent group modulation provides a new strategy for designing polymeric photocatalysts at the molecular level toward high‐efficiency artificial photosynthesis.