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Phase and composition controlled synthesis of cobalt sulfide hollow nanospheres for electrocatalytic water splitting†
Nanoscale ( IF 6.7 ) Pub Date : 2018-02-01 00:00:00 , DOI: 10.1039/c7nr09424h
Xiaoya Ma 1, 2, 3, 4, 5 , Wei Zhang 1, 2, 3, 4, 5 , Yida Deng 1, 2, 3, 4, 5 , Cheng Zhong 1, 2, 3, 4, 5 , Wenbin Hu 1, 2, 3, 4, 5 , Xiaopeng Han 1, 2, 3, 4, 5
Affiliation  

Developing cheap, highly efficient and stable electrocatalysts for both oxygen and hydrogen evolution reactions (OER and HER) is extremely meaningful to realize large-scale implementation of water splitting technology. Herein, we report the phase and composition controlled synthesis of cobalt sulfide (CoSx) hollow nanospheres (HNSs) and their catalytic efficiencies for hydrogen and oxygen evolution reactions in alkaline media. Three CoSx compounds, i.e., Co9S8, Co3S4, and CoS2 HNSs, were precisely synthesized by simply adjusting the molar ratio of carbon disulfide to cobalt acetate using a facile solution-based strategy. Electrochemical results reveal that the as-prepared CoS2 HNSs exhibit superior OER and HER catalytic performance to Co9S8 and Co3S4 HNSs in 1.0 M KOH, with overpotentials of 290 mV for the OER and 193 mV for the HER at 10 mA cm−2, and the corresponding Tafel slopes of 57 and 100 mV dec−1, respectively. In addition, the CoS2 HNSs exhibit remarkable long-term catalytic durability, which is even superior to precious metal catalysts of RuO2 and Pt/C. Moreover, an alkaline electrolyzer assembled using CoS2 HNSs as both anode and cathode materials can achieve 10 mA cm−2 at a low cell voltage of 1.54 V at 60 °C with a faradaic efficiency of 100% for overall water splitting. Further analysis demonstrates that the surface morphology, crystallographic structure and coordination environment of Con+ active sites in combination determine the HER/OER activities in the synthesized binary CoSx series, which would provide insight into the rational design of transition metal chalcogenides for highly efficient hydrogen and oxygen-involved electrocatalysis.

中文翻译:

相和组成控制的用于电催化水分解的硫化钴空心纳米球的合成

开发用于氧气和氢气析出反应(OER和HER)的廉价,高效和稳定的电催化剂,对于大规模实施水分解技术具有极其重要的意义。在这里,我们报告了硫化钴(CoS x)中空纳米球(HNSs)的相和组成控制合成及其在碱性介质中氢和氧逸出反应的催化效率。三种CoS x化合物,Co 9 S 8,Co 3 S 4和CoS 2通过使用简便的基于溶液的策略,只需调节二硫化碳与乙酸钴的摩尔比即可精确合成HNS。电化学结果表明,所制备的CoS 2 HNS在1.0 M KOH中表现出优于Co 9 S 8和Co 3 S 4 HNS的OER和HER催化性能,在10℃时,OER的超电势为290 mV,HER的超电势为193 mV。 mA cm -2,以及相应的Tafel斜率分别为57和100 mV dec -1。此外,CoS 2 HNS具有出色的长期催化耐久性,甚至优于RuO 2的贵金属催化剂和Pt / C。而且,使用CoS 2 HNSs作为阳极和阴极材料组装的碱性电解槽在60°C下在1.54 V的低电池电压下可达到10 mA cm -2,法拉第效率为100%。进一步的分析表明,Co n +活性位点的表面形态,晶体结构和配位环境共同决定了合成的二元CoS x系列中的HER / OER活性,这将为合理设计过渡金属硫属元素化物提供高效的见解。氢和氧参与的电催化。
更新日期:2018-02-01
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