Ngo Thi Yen Linh Bhamu, K.C. Voronova, Anastasiia Jana, Jayasmita Kang, Sung Gu Chung, Jin Suk Choi, Won Mook Jang, Jong Hyun Hur, Seung Hyun Seo, Bora 2024-01-12T02:34:53Z 2024-01-12T02:34:53Z 2022-07-25 2022-12 1385-8947 https://pubs.kist.re.kr/handle/201004/75916 Carbide-oxide heterointerfaces have been known to be responsible for electrochemical activity, however, it is rarely investigated in tungsten carbide-oxide heterostructure for the hydrogen evolution reaction (HER). Furthermore, typical carbide preparation includes carbonization of oxide under gaseous carbon sources at a high temperature, resulting in sintering and collapse of the heterostructures. In this work, nano-sized carbon dots (CDs, similar to 2 nm in diameter) were adopted as carbon sources and dispersed on tungsten oxide nanorods allowing abundant nucleation sites for oxide-to-carbide conversion, resulting in high density of carbide-oxide heteminterfaces. The resulting tungsten carbide-oxide heterostructure decorated with carbon dots (WO(3-x) - WCy/CDs) exhibited superior electrocatalytic activity toward the HER with a low overpotential of 65 mV at a current density of - 10 mA cm(-2) in acidic media. This performance is among the best electrocatalytic activities compared to the state-of-the-art tungsten carbide-based electrocatalysts. Importantly, the single-cell test using WO(3-x) - WCy/CDs as the cathode showed a current density of 10 mA cm(-2) with a cell voltage of only 1.47 V, which is very close to that for Pt/C (1.41 V). In addition, a combined analysis of the X-ray spectroscopic and electrochemical results suggested an optimal W-C ratio in the tungsten carbide-oxide composite to guarantee the high HER activity. Theoretical calculations provided more insight into the carbide-directed enhancement of the electrocatalytic activity of WO(3-x) - WCy/CDs. English Elsevier BV Carbide-directed enhancement of electrochemical hydrogen evolution reaction on tungsten carbide-oxide heterostructure Article 10.1016/j.cej.2022.137915 1 Chemical Engineering Journal, v.450 Chemical Engineering Journal 450 N scie scopus 000830821600008 Engineering, Environmental Engineering, Chemical Engineering Article DOPED CARBON DOTS CATALYTIC-ACTIVITY QUANTUM-DOTS ELECTROCATALYSTS EFFICIENT OXYGEN WATER GROWTH COMPOSITES NANOWIRES Tungsten carbide Tungsten oxide Carbon dots Electrocatalyst Hydrogen evolution reaction