Facile and adjustable production of self–standing oxygen–doped graphene membranes for optimized oxygen evolution electrocatalysis

Owing to abundant resource and affordable price, metal–free carbon has been extensively studied in the field of oxygen reduction reaction, while the related studies on oxygen evolution reaction (OER) are quite few. In this work, a facile and scalable knife coating coupled with annealing strategy is proposed to produce self–standing oxygen–doped graphene membranes (marked as O–GM–T, T represents the annealing temperature). Through systematic characterization and analysis, it is discovered the annealing treatment not only decreases the amount of oxygenic groups, but allows for controlled regulation of the oxygen configurations, leaving only C–OH/C–O–C and CO. Meanwhile, theoretical calculations indicate that the OER activity trend of different oxygen configurations is as follows: –COOH ​> ​CO ​≈ ​C–OH ​> ​C–O–C. Despite the removal of highly active –COOH group through annealing treatment, the resulting O–GM–800 sample maintains good mechanical property and achieves a favorable balance on conductivity, hydrophilicity and catalytic sites. Consequently, it displays significantly improved OER performance compared to the counterparts, making it highly promising for applications in overall water splitting devices. Apparently, our work provides guidance for the rational design and controllable fabrication of self–standing carbon–based catalysts for energy–related reactions.