Tuning Coal into Graphene-Like Nanocarbon for Electrochemical H2O2 Production with Nearly 100% Faraday Efficiency

Electrochemical reduction of O-2 to produce H2O2 provides the most promising alternative to the current anthraquinone process, whereas an electrocatalyst that is cost-effective and has rich resources, excellent oxygen reduction reaction (ORR) activity, and dominant two-electron (2e(-)) selectivity is highly required. Herein, by using inexpensive and earth-abundant anthracite coal as the precursor along with the KOH activation method, a defective graphene-like carbon (DGLC) nanomaterial has been successfully constructed. The as-prepared DGLC material features a graphene-like morphology, a hierarchical porous structure, a high surface area, abundant defects/edges, and a high content of ether functional groups, which endow it with excellent ORR activity, dominant 2e(-) selectivity, and high stability toward H2O2 synthesis in alkaline media. Remarkably, when employed as the electrocatalyst in H-cell, it can achieve a high H2O2 production rate of 355.0 mmol L-1 h(-1) cm(-2) g(cat)(-1) with nearly 100% Faraday efficiency, which is superior to most carbon-based ORR catalysts. Experimental and theoretical studies describe that such high ORR activity and selectivity of DGLC are highly associated with its defect degree and ether groups (C-O-C) content, respectively, which contribute together to boost the superior 2e(-) ORR performance. This finding will be very helpful for designing a carbon-based 2e(-) ORR electrocatalyst toward H2O2 synthesis.

Automated summary

The electrochemical reduction of O-2 to produce H2O2 is a promising alternative to the anthraquinone process, and an efficient electrocatalyst with superior ORR activity and 2e(-) selectivity is in high demand. DGLC, synthesized from anthracite coal, exhibits excellent ORR activity, dominant 2e(-) selectivity, and high stability in H2O2 synthesis. The unique structure and composition of DGLC contribute to its exceptional electrocatalytic performance for H2O2 production.