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Bifunctional LaMn0.3Co0.7O3 Perovskite Oxide Catalyst for Oxygen Reduction and Evolution Reactions: The Optimized eg Electronic Structures by Manganese Dopant.
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2020-05-05 , DOI: 10.1021/acsami.0c03983
Jia Sun 1 , Lei Du 1 , Baoyu Sun 1 , Guokang Han 1 , Yulin Ma 1 , Jiajun Wang 1 , Hua Huo 1 , Chunyu Du 1 , Geping Yin 1
Affiliation  

Perovskite oxides as bifunctional electrocatalysts toward oxygen reduction (ORR) and oxygen evolution reactions (OER) have been investigated for decades because of the flexible and adjustable electronic structures. For example, by optimizing the strength of the Co–O bond, the ORR and OER activity of a typical perovskite oxide, LaCoO3, can be improved, but they are still unsatisfying. The insufficient insights into the effects of secondary metal dopants at the B-site on the electronic structure and activity, especially for ORR, significantly limit the R&D of bifunctional perovskite oxide catalysts. In this work, a series of LaMnxCo1–xO3 (x = 0, 0.25, 0.3, 0.35, 0.5, 1) catalysts are prepared by a polyol-assisted solvothermal method to investigate the structure–property relationships between the B-site metal substitution and the electrochemical performance of perovskite oxides catalysts. The optimized LaMn0.3Co0.7O3 catalyst demonstrates an enhanced half-wave potential of 0.72 V for ORR, 52 mV higher than that of the pristine LaCoO3 (0.668 V). Meanwhile, the OER overpotential of LaMn0.3Co0.7O3 catalyst is 416 mV, which is reduced by 64 mV compared to LaCoO3 (480 mV). It is revealed that the appropriate Mn dopant efficiently optimizes the covalency of Co–O bonds and significantly reduces the eg orbit-filling electron from 1.23 of pristine LaCoO3 to 1.02 in LaMn0.3Co0.7O3 (very close to theoretical value 1). This work paves a new way to design and synthesize bifunctional perovskite oxide electrocatalyst for ORR and OER.

中文翻译:

用于氧还原和放出反应的双功能LaMn0.3Co0.7O3钙钛矿氧化物催化剂:锰掺杂剂优化的电子结构。

由于柔性和可调节的电子结构,钙钛矿氧化物作为用于氧还原(ORR)和氧释放反应(OER)的双功能电催化剂已被研究了数十年。例如,通过优化Co-O键的强度,可以提高典型钙钛矿氧化物LaCoO 3的ORR和OER活性,但仍不令人满意。对B位上的次要金属掺杂剂对电子结构和活性(特别是对于ORR)的影响的见解不足,极大地限制了双功能钙钛矿氧化物催化剂的研发。在这项工作中,一系列LaMn x Co 1– x O 3x= 0、0.25、0.3、0.35、0.5、1)通过多元醇辅助溶剂热法制备催化剂,以研究B位金属取代与钙钛矿氧化物催化剂的电化学性能之间的结构-性质关系。优化的LaMn 0.3 Co 0.7 O 3催化剂对ORR的半波电势提高了0.72 V,比原始LaCoO 3(0.668 V)高52 mV 。同时,LaMn 0.3 Co 0.7 O 3催化剂的OER过电位为416 mV,与LaCoO 3相比降低了64 mV。(480 mV)。据透露,在适当的Mn掺杂剂有效地优化了的CO-O键的共价性和显著降低电子轨道填充电子从原始LaCoO 1.23 3至1.02在兰姆0.30.7 ø 3(非常接近于理论值1) 。这项工作为设计和合成用于ORR和OER的双功能钙钛矿氧化物电催化剂开辟了一条新途径。
更新日期:2020-05-05
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