Metal-Free Oxygen Evolution and Oxygen Reduction Reaction Bifunctional Electrocatalyst in Alkaline Media: From Mechanisms to Structure-Catalytic Activity Relationship
- Title
- Metal-Free Oxygen Evolution and Oxygen Reduction Reaction Bifunctional Electrocatalyst in Alkaline Media: From Mechanisms to Structure-Catalytic Activity Relationship
- Author
- 이상욱
- Keywords
- Doped C3N4 catalyst; Density functional calculations; OER; ORR; Fuel cell
- Issue Date
- 2018-04
- Publisher
- AMER CHEMICAL SOC
- Citation
- ACS SUSTAINABLE CHEMISTRY & ENGINEERING, v. 6, no. 4, page. 4973-4980
- Abstract
- We have systematically investigated a metal-free bifunctional electrocatalyst of heteroatom-doped carbon nitride (X-Y-C3N4, where X and Y indicate the dopant and doping site on C3N4, respectively) for oxygen evolution and oxygen reduction reactions (OER and ORR), considering the possible reaction pathways based on the Eley-Rideal (ER) mechanism as well as the doping effects on electrocatalytic activity. In this work, the relative stability of O* and OOH* intermediates was a key factor in determining the ORR pathway; accordingly, ORR follows a two-step reaction pathway governed by O* rather than a four-step reaction pathway governed by OOH*. In addition, we found that P and S codoped C3N4 shows superior OER/ORR activity with synergistic geometric and electronic effects, which coordinatively increase unsaturated sp(3)-C via structural deformation and improve electrical conductance by modulating the electronic structure with extra electrons from dopants. In particular, PCSC-C3N4 (C3N4 with P and S codoped at the carbon site) shows better bifunctional performance of OER/ORR with competitive overpotentials at 0.42 and 0.27 V, respectively, compared to conventional Pt and RuO2 catalysts. Therefore, our theoretical investigations suggest that PCSC-C3N4 is the most promising bifunctional OER/ORR electrocatalyst with synergistic effects in several electrochemical devices.
- URI
- https://pubs.acs.org/doi/10.1021/acssuschemeng.7b04608https://repository.hanyang.ac.kr/handle/20.500.11754/118378
- ISSN
- 2168-0485
- DOI
- 10.1021/acssuschemeng.7b04608
- Appears in Collections:
- GRADUATE SCHOOL[S](대학원) > BIONANOTECHNOLOGY(바이오나노학과) > Articles
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