Universal molecular-confined synthesis of interconnected porous metal oxides-N-C frameworks for electrocatalytic water splitting
Universal molecular-confined synthesis of interconnected porous metal oxides-N-C frameworks for electrocatalytic water splitting
复制标题
DOI：
10.1016/j.nanoen.2018.04.009
复制
发表时间：
2018-06
期刊：
影响因子：
17.6
通讯作者：
Bo You;Yadong Zhang;Peiqun Yin;D. Jiang;Yujie Sun
中科院分区：
文献类型：
--
作者：
Bo You;Yadong Zhang;Peiqun Yin;D. Jiang;Yujie Sun
以低成本合理合成用于水裂解（析氢和析氧反应，HER和OER）的高性能电催化剂是高度期望的，但仍然是一个关键挑战。在此，我们报道了一种多功能的分子限制路线来构建具有互连构型的强耦合金属氧化物-N-C框架。通过在琼脂糖水凝胶中简单地用乙二胺四乙酸二钠盐（EDTA）螯合各种过渡金属离子并随后碳化，可以制备具有强偶联金属氧化物（例如，锰、铁、钴、镍和它们的混合氧化物）可以制备为先进的非贵金属水裂解电催化剂。例如，所得的Co 3 O 4-N-C骨架具有153 m2 g-1的高表面积和1.23%的中等氮含量，需要324 mV的过电位以在0.1 M KOH中提供10 mA cm-2的电流密度用于OER，其上级于商业RuO 2催化剂。密度泛函理论（DFT）计算结果表明，N-C与Co 3 O 4之间的强耦合调节了Co的高价活性位的局域电子结构，保证了OER中间体的最佳吸附能.此外，由Co 3 O 4-N-C衍生的Co2 P-N-C电催化剂在1.0 M KOH下也表现出优异的HER性能，具有139 mV的低过电位，达到10 mA cm−2，45 mV dec− 1的小塔菲尔斜率和令人印象深刻的稳定性，强调了我们合成策略的多功能性。
The rational synthesis of high performance electrocatalysts at low cost for water splitting (hydrogen and oxygen evolution reaction, HER and OER) is highly desirable but remains a key challenge. Herein, we report a versatile molecular-confining route to construct strongly coupled metal oxides-N-C frameworks with interconnected configuration. By simply chelating various transition metal ions with ethylenediaminetetraacetic acid disodium salt (EDTA) in agarose hydrogel and subsequent carbonization, the high specific surface area porous N-C frameworks with strongly coupled metal oxides (e.g., manganese, iron, cobalt, nickel and their mixed oxides) can be prepared as advanced nonprecious water splitting electrocatalysts. For instance, the resulting Co3O4-N-C frameworks with the high surface area of 153 m2g−1, and the moderate nitrogen content of 1.23%, require an overpotential of 324 mV to afford a current density of 10 mA cm−2in 0.1 M KOH for OER, superior to commercial RuO2catalysts. Density functional theory (DFT) calculations reveal that the strong coupling between N-C and Co3O4tunes the local electronic structure of Co for high-valence active sites and assures optimal adsorption energies of OER intermediates. Moreover, Co2P-N-C electrocatalysts derived from Co3O4-N-C also exhibit excellent HER performance under 1.0 M KOH with a low overpotential of 139 mV to reach 10 mA cm−2, a small Tafel slope of 45 mV dec−1and impressive stability, underscoring the versatility of our synthetic strategy.