Highly Efficient Acidic Electrosynthesis of Hydrogen Peroxide in Air-Fed Conditions Accelerated by a Three-Dimensional Cross-Linked Carbon Nanoweb Catalyst

Electrosynthesis of hydrogen peroxide (H2O2) via a two-electron oxygen reduction reaction (2e– ORR) provides a green and sustainable alternative to the current energy-intensive anthraquinone process. However, the development of inexpensive and efficient electrocatalysts under acidic and air-fed conditions remains a challenge. Herein, we constructed a three-dimensional nitrogen-doped carbon nanoweb (3D-N-CNW) electrocatalyst by using a naturally porous cross-linked skeleton of water hyacinth as a raw material. The 3D-N-CNW shows an ultrahigh specific surface area of 1464 m2 g–1 with interconnected hierarchical porous architecture, and abundant carbon defects, resulting in excellent 2e– ORR activity with high onset potential (0.64 V) and H2O2 selectivity (∼93%), which is the best-performing carbon-based catalyst reported in acidic media. Impressively, the flow cell utilizing 3D-N-CNW achieves an exceptionally high H2O2 yield of 4289 mg L–1 h–1 under air self-breathing conditions, enabling ultrafast degradation of representative organic pollutants. Theoretical calculations and control experiments reveal that the 3D cross-linked network facilitates mass transport and creates an enriched O2 microenvironment to promote the 2e– ORR to highly efficient H2O2 production. This work provides a low-cost, readily scalable, and convenient route for the construction of advanced carbon-based electrocatalysts from natural biomass materials; it can also be expected in other renewable areas.