Electrocatalytic Production of H2O2 by Selective Oxygen Reduction Using Earth-Abundant Cobalt Pyrite (CoS2),ACS Catalysis

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Electrocatalytic Production of H2O2 by Selective Oxygen Reduction Using Earth-Abundant Cobalt Pyrite (CoS2)
ACS Catalysis ( IF 11.3 ) Pub Date : 2019-08-01 00:00:00 , DOI: 10.1021/acscatal.9b02546
Hongyuan Sheng ₁ , Eric D. Hermes ₁ , Xiaohua Yang _{1,

2} , Diwen Ying _{1,

3} , Aurora N. Janes ₁ , Wenjie Li ₁ , J. R. Schmidt ₁ , Song Jin ₁

Affiliation

Decentralized on-site production of hydrogen peroxide (H₂O₂) relies on efficient, robust, and inexpensive electrocatalysts for the selective two-electron (2e^–) oxygen reduction reaction (ORR). Here, we combine computations and experiments to demonstrate that cobalt pyrite (CoS₂), an earth-abundant transition-metal compound, is both active and selective toward 2e^– ORR in the acidic solution. CoS₂ nanomaterials drop-casted on the rotating ring-disk electrode (RRDE) showed selective and efficient H₂O₂ formation in 0.05 M H₂SO₄ at high catalyst loadings, with their operational stability evaluated by structural and surface analyses. CoS₂ nanowires directly grown on the high-surface-area carbon fiber paper electrode boosted the overall performance of bulk ORR electrolysis and the H₂O₂ product was chemically quantified to yield a ∼70% H₂O₂ selectivity at 0.5 V vs reversible hydrogen electrode (RHE), in good agreement with the RRDE results. Computations suggested the modest binding of OOH* adsorbate on the single Co site of CoS₂ and the kinetically disfavored O–O bond scission due to the lack of active site ensembles in the crystal structure, consistent with the experimentally observed activity and selectivity. CoS₂ also catalyzes 2e^– ORR with less activity and selectivity in the noncorrosive neutral solution. This work opens up the exploration of diverse earth-abundant transition-metal compounds in search of highly active and selective electrocatalysts for efficient H₂O₂ production.

中文翻译：

富地球黄铁矿（CoS ₂）选择性氧化还原制H ₂ O ₂的电催化作用

分散现场生产过氧化氢（H的₂ ö ₂）依赖于有效，鲁棒和廉价的电催化剂用于选择性两电子（2E ^-）氧还原反应（ORR）。在这里，我们结合计算和实验证明了，富含铁的过渡金属化合物黄铁矿（CoS ₂）在酸性溶液中对2e ^- ORR既有活性，又具有选择性。滴铸在旋转圆盘电极（RRDE）上的CoS ₂纳米材料在0.05 MH ₂ SO _4中表现出选择性和有效的H ₂ O ₂形成在高催化剂负载下，通过结构和表面分析评估其操作稳定性。直接在高表面积碳纤维纸电极上生长的CoS ₂纳米线提高了整体ORR电解的整体性能，并且对H ₂ O ₂产物进行了化学定量，在0.5 V时相对于可逆，H ₂ O _2的选择性为〜70％H ₂ O ₂。氢电极（RHE）与RRDE结果非常吻合。计算表明OOH *吸附物在CoS ₂的单个Co位点上的适度结合以及由于晶体结构中缺乏活性位点聚集而在动力学上不利的O–O键断裂，这与实验观察到的活性和选择性一致。在非腐蚀性中性溶液中，CoS ₂还能以较低的活性和选择性催化2e ^- ORR。这项工作开启了对多种地球富集过渡金属化合物的探索，以寻找高效生产H ₂ O ₂的高活性和选择性电催化剂。

更新日期：2019-08-01

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