铑掺杂到钴酸镧 (LaCoO3) 钙钛矿中的作用以及在碱性介质中诱导析氧和还原反应的双功能活性
Arabian Journal of Chemistry
(
IF
5.2
)
Pub Date : 2022-09-16
, DOI:
10.1016/j.arabjc.2022.104256
Mohamed A. Ghanem
,
Mabrook S. Amer
,
Prabhakarn Arunachalam
,
Abdullah M. Al-Mayouf
,
Mark T. Weller
过渡金属氧化物，尤其是钙钛矿，被认为是碱性溶液中析氧（OER）和氧还原（ORR）反应的有效电催化剂。在这里，通过固相合成的方法制备 了一系列化学式 LaCo 1-x Rh x O 3 (LCRO, 0.1 ≤ x ≤ 0.70) 的镧钴铑氧化物钙钛矿，并评估了它们的双功能电催化活性。 OER 和 ORR。LCRO的结晶度、形貌、表面和电催化特性与铑含量显着相关。 LaCo 0.7 Rh 0.3 O 3x = 0.3 的电催化剂表现出增强的电催化双功能性能，OER/ORR 起始电位比 HRE 显着降低，为 1.38/0.73 V，Tafel 斜率更小（116/90 mV/dec），电荷转移电阻低，这是最在其他研究的比例中是一种有效的催化剂，并且优于原始的镧钴氧化物基准电催化剂。LaCo 0.7 Rh 0.3 O 3电极表现出良好的双功能电催化行为和长期耐久性，具有 OER 和 ORR 起始电位间隙（ΔE = E OER - E ORR) 仅为 0.65 V，这可归因于在掺杂较大尺寸的 Rh 离子时富氧空位、晶格膨胀和改善的电导率。LaCo 1-x Rh x O 3催化剂由丰富的材料制成，这些材料具有高活性双功能 OER 和 ORR 电催化剂的潜力。
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Role of rhodium doping into lanthanum cobalt oxide (LaCoO3) perovskite and the induced bifunctional activity of oxygen evolution and reduction reactions in alkaline medium
Transition metal oxides, especially perovskites, have been considered effective electrocatalysts for the oxygen evolution (OER) and oxygen reduction (ORR) reactions in an alkaline solution. Here, a series of lanthanum cobalt rhodium oxide perovskites with the chemical formula LaCo1-xRhxO3 (LCRO, 0.1 ≤ x ≤ 0.70) were prepared through the approach of solid-phase synthesis and their bifunctional electrocatalytic activity was assessed for both the OER and ORR. The crystallinity, morphology, surface, and electrocatalytic features of the LCRO were significantly correlated with the rhodium content. The LaCo0.7Rh0.3O3 electrocatalysts with x = 0.3 showed enhanced electrocatalytic bifunctional performance with a substantially lower OER/ORR onset potential of 1.38/0.73 V vs HRE, smaller Tafel slope (116/90 mV/dec), and low charge-transfer resistance, which is the most efficient catalyst among the other studied ratios and superior to the pristine lanthanum cobalt oxide benchmark electrocatalysts. The LaCo0.7Rh0.3O3 electrode exhibit good bifunctional electrocatalytic behavior and long-term durability with an OER and ORR onset potential gap (ΔE = EOER − EORR) of only 0.65 V, which could be credited to the enriched oxygen vacancies, lattice expansion and the improved electrical conductivity upon the doping of larger size of Rh ions. The LaCo1-xRhxO3 catalysts are obtained from abundant materials that have the potential of highly-active bifunctional OER and ORR electrocatalysts.
更新日期：2022-09-16