Vinylene‐Linked Covalent Organic Frameworks with Ammonium‐Promoted‐Proton Transfer for Photocatalysis of H2O2 Evolution

Covalent organic frameworks (COFs) have emerged as effective photocatalysts for the environmentally friendly synthesis of hydrogen peroxide (H2O2) through the oxygen reduction reaction (ORR) under solar sunlight. Besides electron transfer in an ORR process, proton transport also serves as an important role in promoting kinetic rate, which was majorly improved via modifying the chemical structures of COFs, but seldom to be explored through a simple additive composition. In work, we report the preparation of two new vinylene‐linked COFs termed g‐TDM‐COF and g‐TBD‐COF, respectively. The methoxyl substituents pended on the backbones of these COFs rendered them with hydrogen bond donating capabilities. Combined with their substantial semiconducting properties, the COFs enable photocatalysis of hydroperoxide (H2O2) production. Simply compositing these COFs with ammonium ions markedly improved the photoelectric properties, leading to an over 8‐fold enhancement of photocatalytic H2O2 production relative to the neat COFs, and an increase in apparent quantum yields (AQYs) from 0.70% to 4.22% at 500 nm. Such phenomenon could be attributed to the efficient interaction ammonium ions with the COFs via hydrogen‐bond interaction, thus favorable for broading light‐harvesting, narrowing band gaps, and strengthening proton conductivity, As a consequence, their photocatalytic performance could be distinctly enhanced.