The development of e cient earth-abundant electrocatalysts for oxygen reduction, oxygen evolution, and hydrogen evolution reactions(ORR, OER, and HER) is important for future energy conversion and energy storage devic...The development of e cient earth-abundant electrocatalysts for oxygen reduction, oxygen evolution, and hydrogen evolution reactions(ORR, OER, and HER) is important for future energy conversion and energy storage devices, for which both rechargeable Zn–air batteries and water splitting have raised great expectations. Herein, we report a single-phase bimetallic nickel cobalt sulfide((Ni,Co)S_2) as an e cient electrocatalyst for both OER and ORR. Owing to the synergistic combination of Ni and Co, the(Ni,Co)S_2 exhibits superior electrocatalytic performance for ORR, OER, and HER in an alkaline electrolyte, and the first principle calculation results indicate that the reaction of an adsorbed O atom with a H_2O molecule to form a *OOH is the potential limiting step in the OER. Importantly, it could be utilized as an advanced air electrode material in Zn–air batteries, which shows an enhanced charge–discharge performance(charging voltage of 1.71 V and discharge voltage of 1.26 V at 2 mA cm^(-2)), large specific capacity(842 mAh g_(Zn)^(-1) at 5 mA cm^(-2)), and excellent cycling stability(480 h). Interestingly, the(Ni,Co)S_2-based Zn–air battery can e ciently power an electrochemical water-splitting unit with(Ni,Co)S_2 serving as both the electrodes. This reveals that the prepared(Ni,Co)S_2 has promising applications in future energy conversion and energy storage devices.展开更多
Effectively controlling the selectivity of C_(2) oxygenates is desirable for electrocatalytic CO_(2) reduction.Copper catalyst has been considered as the most potential for reducing CO_(2) to C_(2) products,but it sti...Effectively controlling the selectivity of C_(2) oxygenates is desirable for electrocatalytic CO_(2) reduction.Copper catalyst has been considered as the most potential for reducing CO_(2) to C_(2) products,but it still suffers from low C_(2) selectivity,high overpotential,and competitive hydrogen evolution reaction(HER).Here,we propose a design strategy to introduce a second metal that weakly binds to H and a functional ligand that provides hydrogen bonds and protons to achieve high selectivity of C_(2)oxygenates and effective suppression of HER on the Cu(100)surface simultaneously.Seven metals and eleven ligands are screened using first-principles calculations,which shows that Sn is the most efficient for inhibiting HER and cysteamine(CYS)ligand is the most significant in reducing the limiting potential of^(*)CO hydrogenation to^(*)CHO.In the post C-C coupling steps,a so-called“pulling effect”that transfers H in the CYS ligand as a viable proton donor to the C_(2)intermediate to form an H bond,can further stabilize the OH group and facilitate the selection of C_(2)products toward oxygenates.Therefore,this heterogeneous electrocatalyst can effectively reduce CO_(2)to ethanol and ethylene glycol with an ultra-low limiting potential of-0.43 V.This study provides a new strategy for effectively improving the selectivity of C_(2)oxygenates and inhibiting HER to achieve advanced electrocatalytic CO_(2)reduction.展开更多
MXenes have exhibited great potential as cost-effective electrocatalysts for hydrogen evolution reaction(HER). However, insight into the origin of activity is still missing. Herein, on the basis of a systematical inve...MXenes have exhibited great potential as cost-effective electrocatalysts for hydrogen evolution reaction(HER). However, insight into the origin of activity is still missing. Herein, on the basis of a systematical investigation of the HER performance of 20 MXenes(M_2NO_2 and M_2CO_2, M = Sc, Ti, V, Cr, Zr, Nb, Mo,Hf, Ta and W), a Fermi-abundance model is proposed to understand variation of the activity in different MXenes. It is found that the occupied p electronic states of surface O atoms play a decisive role in the HER activity of MXenes. More importantly, Ti_2NO_2 and Nb_2NO_2 are found to be promising HER electrocatalysts with the free energy for hydrogen adsorption close to zero. This work not only provides possible catalysts for HER, the developed Fermi-abundance model but also is applicable to other two-dimensional materials and may serve as a simple descriptor of the intrinsic HER activity.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11474137 and 11674143)Program for Changjiang Scholars and Innovative Research Team in University (IRT 16R35)+1 种基金the Fundamental Research Funds for the Central Universities (Grant Nos. LZUMMM2018017, lzujbky-2018-121)the support of Ministry of Education (MOE2016-T2-2-138,Singapore),for research conducted at the National University of Singapore
文摘The development of e cient earth-abundant electrocatalysts for oxygen reduction, oxygen evolution, and hydrogen evolution reactions(ORR, OER, and HER) is important for future energy conversion and energy storage devices, for which both rechargeable Zn–air batteries and water splitting have raised great expectations. Herein, we report a single-phase bimetallic nickel cobalt sulfide((Ni,Co)S_2) as an e cient electrocatalyst for both OER and ORR. Owing to the synergistic combination of Ni and Co, the(Ni,Co)S_2 exhibits superior electrocatalytic performance for ORR, OER, and HER in an alkaline electrolyte, and the first principle calculation results indicate that the reaction of an adsorbed O atom with a H_2O molecule to form a *OOH is the potential limiting step in the OER. Importantly, it could be utilized as an advanced air electrode material in Zn–air batteries, which shows an enhanced charge–discharge performance(charging voltage of 1.71 V and discharge voltage of 1.26 V at 2 mA cm^(-2)), large specific capacity(842 mAh g_(Zn)^(-1) at 5 mA cm^(-2)), and excellent cycling stability(480 h). Interestingly, the(Ni,Co)S_2-based Zn–air battery can e ciently power an electrochemical water-splitting unit with(Ni,Co)S_2 serving as both the electrodes. This reveals that the prepared(Ni,Co)S_2 has promising applications in future energy conversion and energy storage devices.
基金supported by the National Natural Science Foundation of China(Grant No.22033002,21525311,21773027)the Scientific Research Foundation of Graduate School of Southeast University(YBPY1920)+1 种基金the China Postdoctoral Science Foundation(Grant No.2020M681450)the China Scholarship Council(CSC,201906090150)。
文摘Effectively controlling the selectivity of C_(2) oxygenates is desirable for electrocatalytic CO_(2) reduction.Copper catalyst has been considered as the most potential for reducing CO_(2) to C_(2) products,but it still suffers from low C_(2) selectivity,high overpotential,and competitive hydrogen evolution reaction(HER).Here,we propose a design strategy to introduce a second metal that weakly binds to H and a functional ligand that provides hydrogen bonds and protons to achieve high selectivity of C_(2)oxygenates and effective suppression of HER on the Cu(100)surface simultaneously.Seven metals and eleven ligands are screened using first-principles calculations,which shows that Sn is the most efficient for inhibiting HER and cysteamine(CYS)ligand is the most significant in reducing the limiting potential of^(*)CO hydrogenation to^(*)CHO.In the post C-C coupling steps,a so-called“pulling effect”that transfers H in the CYS ligand as a viable proton donor to the C_(2)intermediate to form an H bond,can further stabilize the OH group and facilitate the selection of C_(2)products toward oxygenates.Therefore,this heterogeneous electrocatalyst can effectively reduce CO_(2)to ethanol and ethylene glycol with an ultra-low limiting potential of-0.43 V.This study provides a new strategy for effectively improving the selectivity of C_(2)oxygenates and inhibiting HER to achieve advanced electrocatalytic CO_(2)reduction.
基金supported by the National Natural Science Foundation for Distinguished Young Scholar (21525311)the National Key R&D Program of China (2017YFA0204800)+3 种基金the National Natural Science Foundation of China (21773027, 21703032)Jiangsu 333 Project (BRA2016353)the Scientific Research Foundation of Graduate School of Southeast University in Chinathe Fundamental Research Funds for the Central Universities of China
文摘MXenes have exhibited great potential as cost-effective electrocatalysts for hydrogen evolution reaction(HER). However, insight into the origin of activity is still missing. Herein, on the basis of a systematical investigation of the HER performance of 20 MXenes(M_2NO_2 and M_2CO_2, M = Sc, Ti, V, Cr, Zr, Nb, Mo,Hf, Ta and W), a Fermi-abundance model is proposed to understand variation of the activity in different MXenes. It is found that the occupied p electronic states of surface O atoms play a decisive role in the HER activity of MXenes. More importantly, Ti_2NO_2 and Nb_2NO_2 are found to be promising HER electrocatalysts with the free energy for hydrogen adsorption close to zero. This work not only provides possible catalysts for HER, the developed Fermi-abundance model but also is applicable to other two-dimensional materials and may serve as a simple descriptor of the intrinsic HER activity.