2D intrinsically defective RuO2/Graphene heterostructures as All-pH efficient oxygen evolving electrocatalysts with unprecedented activity. (December 2020)

• Record Type: Journal Article
• Authors: Li, Yaguang; Wang, Yi; Lu, Jianmin; Yang, Bing; San, Xingyuan; Wu, Zhong-Shuai
• Is Part Of: Nano energy. Volume 78(2020)
• Publication Date: 2020-12
• Subjects: Oxygen evolution reaction -- Defective RuO2 -- Confined oxygenation -- Graphene -- Heterostructure; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2020.105185
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Exploring highly active and stable oxygen evolving electrocatalysts is the key for electrochemical water splitting and renewable chemical conversion. RuO2 is one of the benchmark oxygen evolving electrocatalysts, but remains challenging in high activity in all-pH electrolytes. Herein, we report a confined oxygenation strategy using the finite oxygen species from graphene oxide to synthesize two dimensional (2D) heterostructures of intrinsically defective RuO2 nanocrystals uniformly grown on graphene (2D D-RuO2 /G), showing ultrathin thickness of 9 nm, high specific surface area of 125 m 2 g −1, enriched hydroxylated surface and notably intrinsic defective RuO2 with low Ru–O coordination number of 5. Consequently, 2D D-RuO2 /G exhibits a robust stability and an extraordinary oxygen evolution reaction (OER) performance both in acidic and alkaline solutions, achieving a current density of 10 mA cm −2 at the overpotential of 169 and 175 mV, and a water oxidation turn over frequency of 1.07 and 1.25 S −1 at 270 mV, respectively, corresponding to 344 mV of total overpotential at 10 mA cm −2 in acidic and alkaline electrolytes, which greatly exceeds the state-of-the-art of pH-universal OER electrocatalysts. Theoretical studies indicate that intrinsic defective Ru sites can enhance the adsorption and accelerate the decomposition of hydroxyl groups to boost the OER activity. This confined oxygenation strategy provides the opportunities to construct 2D advanced defective OER electrocatalysts in all-pH electrolytes. Graphical abstract: Two dimensional heterostructures of intrinsically defective RuO2 nanocrystals uniformly grown on graphene achieve a low overpotential of 169 and 175 mV for 10 mA cm −2 in acidic and alkaline electrolytes, respectively, exceeding the state-of-the-art of pH-universal oxygen evolving electrocatalysts. Image 1 Highlights: The graphene oxide could used to synthesize two dimensional heterostructures of RuO2 and graphene (2D D-RuO2 /G). The 2D D-RuO2 /G showed intrinsic defective RuO2 with low Ru-O coordination number of 5. The 2D D-RuO2 /G exhibited the ultrathin thickness of 9 nm and high specific surface area of 125 m 2 g -1 . 2D D-RuO2 /G achieved 10 mA cm −2 at the overpotential of 169 and 175 mV in acidic and alkaline solutions, respectively. ● 2D D-RuO2 /G had a 344 mV of total overpotential at 10 mA cm −2 in acidic and alkaline electrolytes.