Electrochemical production of hydrogen peroxide by non-noble metal-doped g-C3N4 under a neutral electrolyte.

Electrochemical oxygen reduction (ORR) for the production of clean hydrogen peroxide (H2O2) is an effective alternative to industrial anthraquinone methods. The development of highly active, stable, and 2e- ORR oxygen reduction electrocatalysts while suppressing the competing 4e- ORR pathway is currently the main challenge. Herein, bimetallic doping was successfully achieved based on graphitic carbon nitride (g-C3N4) with the simultaneous introduction of K and Co, whereby 2D porous K-Co/CNNs nanosheets were obtained. The introduction of Co promoted the selectivity for H2O2, while the introduction of K not only promoted the formation of 2D nanosheets of g-C3N4, but also inhibited the ablation of H2O2 by K-Co/CNNs. Electrochemical studies showed that the selectivity of H2O2 in K-Co/CNNs under neutral electrolyte was as high as 97%. After 24 h, the H2O2 accumulation of K-Co/CNNs was as high as 31.7 g L-1. K-Co/CNNs improved the stability of H2O2 by inhibiting the ablation of H2O2, making it a good 2e- ORR catalyst and providing a new research idea for the subsequent preparation of H2O2.

Transition metal single atom-optimized g-C3N4 for the highly selective electrosynthesis of H2O2 under neutral electrolytes.

Neutral electrosynthesis of H2O2via the 2e- ORR is attractive for numerous applications, but the low activity and high cost of electrocatalysts have become important constraints. Therefore, the development of cheap and efficient electrocatalysts for the 2e- ORR is necessary. Herein, we report the embedding of transition metal single atoms (TM SAs) in g-C3N4 nanosheets (CNNS). The introduction of TM SAs increases the N-CN content and reduces the C-C/CC content in CNNS, which contributes to the increased selectivity of TM SA/CNNS for the 2e- ORR. TM SA is the main reason for the enhanced activity of the 2e- ORR. Based on the results obtained by replacing a series of TM SA, the Ni0.10 SA/CNNS with optimal N-CN content exhibited the best selectivity (∼98%) and highest yield of H2O2 (∼503 mmol gcat-1 h-1), which is ∼14.6 times higher than that of CNNS (∼34.4 mmol gcat-1 h-1). Other TM SA/CNNS also exhibited high activity and selectivity. This study demonstrates the ability of TM SA to modulate the selectivity and activity of CNNS, making it a promising candidate for the 2e- ORR and providing more reference ideas for the preparation of H2O2.