Enhanced electrochemical oxygen and hydrogen evolution reactions using an NU-1000@NiMn-LDHS composite electrode in alkaline electrolyte

2020 ◽  
Vol 56 (49) ◽  
pp. 6652-6655 ◽  
Author(s):  
Soheila Sanati ◽  
Reza Abazari ◽  
Ali Morsali

A well-designed NU-1000@NiMn-LDHS (NU@LDHS) composite can offer efficient electrocatalytic performance with ultralow HER and OER overpotentials of 93 and 129 mV, respectively, at a current density of 10 mA cm−2 in 2 M KOH.

2020 ◽  
Vol 56 (56) ◽  
pp. 7702-7705 ◽  
Author(s):  
Lei Guo ◽  
Xue Bai ◽  
Hui Xue ◽  
Jing Sun ◽  
Tianshan Song ◽  
...  

A 3D hierarchical Bi-doped CoP nanoflowers electrocatalyst is developed based on a MOF self-sacrifice strategy. The 3% Bi/CoP catalyst delivers a current density of 10 mA cm−2 at low overpotentials of 122 mV in alkaline electrolyte and 150 mV in acidic electrolyte.


2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.


1970 ◽  
Vol 43 (1) ◽  
pp. 103-116 ◽  
Author(s):  
M Ashraful Islam Molla ◽  
Mithun Sarker ◽  
AKM Fazle Kibria

Redox behaviors and hydrogen evolution efficiencies of Pd and Mo deposited Pd electrodes have been investigated in 30wt.% KOH electrolyte by cyclic voltammetry. Cyclic voltammograms of Pd electrode in between the potential range - 1.05 V to + 0.75 V showed two couples of redox peaks for the transformations of Pd(0) ←→ Pd(OH)2 and Pd(OH)2 ←→ PdOOH, an anodic peak for the desorption of diffusional hydrogen (dH) and hydrogen and oxygen evolutions at the terminal potential regions. Hydrogen evolution efficiency found decreased with time and then reached to a stable condition after 35 minutes. In presence of deposited Mo, the electrode stable condition appeared after 10 minutes only. Pd found predominates over deposited Mo. Both the Pd(0) ←Pd(OH)2 and Mo(0) ← Mo(OH)2 transformations appeared at the same potential value. Mo stopped the movement of hydrogen adsorption and absorption region of Pd electrode towards negative potential direction. It increased the hydrogen evolution efficiency of Pd electrode remarkably. At the potentials - 1.1 V, - 1.2 V, - 1.25 V and - 1.3 V, currents for Pd + Mo system found 1.44, 1.25, 1.20, 1.23 times higher than those of Pd electrode. Mo also showed hydrogen migratory role to the fraction of Pd surface covered by it. Hydrogen evolution reactions (HER) over Pd and Pd + Mo surfaces seemed followed similar mechanisms. Tafel plots for the HER for both the systems showed two Tafel regions. Exchange current density values (io) for the low and high overpotential regions of Pd + Mo system showed 2.85 times and 1.29 times higher values than those of Pd electrode. Key words: Pd, Pd-Mo, Hydrogen evolution efficiency, Hydrogen evolution reactions (HER) DOI: 10.3329.bjsir.v43i1.861 Bangladesh J. Sci. Ind. Res. 43(1), 103-116, 2008


Science ◽  
2021 ◽  
Vol 372 (6546) ◽  
pp. 1074-1078
Author(s):  
Jianan Erick Huang ◽  
Fengwang Li ◽  
Adnan Ozden ◽  
Armin Sedighian Rasouli ◽  
F. Pelayo García de Arquer ◽  
...  

Carbon dioxide electroreduction (CO2R) is being actively studied as a promising route to convert carbon emissions to valuable chemicals and fuels. However, the fraction of input CO2 that is productively reduced has typically been very low, <2% for multicarbon products; the balance reacts with hydroxide to form carbonate in both alkaline and neutral reactors. Acidic electrolytes would overcome this limitation, but hydrogen evolution has hitherto dominated under those conditions. We report that concentrating potassium cations in the vicinity of electrochemically active sites accelerates CO2 activation to enable efficient CO2R in acid. We achieve CO2R on copper at pH <1 with a single-pass CO2 utilization of 77%, including a conversion efficiency of 50% toward multicarbon products (ethylene, ethanol, and 1-propanol) at a current density of 1.2 amperes per square centimeter and a full-cell voltage of 4.2 volts.


2017 ◽  
Vol 5 (16) ◽  
pp. 7564-7570 ◽  
Author(s):  
Peili Zhang ◽  
Hong Chen ◽  
Mei Wang ◽  
Yong Yang ◽  
Jian Jiang ◽  
...  

A hierarchically structured Ni–Co–P film exhibits remarkable activity toward the hydrogen evolution reaction with a current density of −10 mA cm−2 at −30 mV vs. the RHE.


Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2347
Author(s):  
Zhi Chen ◽  
Ying Zhao ◽  
Yuxiao Gao ◽  
Zexing Wu ◽  
Lei Wang

Exploiting efficient electrocatalysts for hydrogen evolution reactions (HERs) is important for boosting the large-scale applications of hydrogen energy. Herein, MoP-RuP2 encapsulated in N,P-codoped carbon (MoP-RuP2@NPC) with abundant interfaces were prepared via a facile avenue with the low-toxic melamine phosphate as the phosphorous resource. Moreover, the obtained electrocatalyst possessed a porous nanostructure, had abundant exposed active sites and improved the mass transport during the electrocatalytic process. Due to the above merits, the prepared MoP-RuP2@NPC delivered a greater electrocatalytic performance for HERs (50 mV@10 mA cm−2) relative to RuP2@NPC (120 mV) and MoP@NPC (195 mV) in 1 M KOH. Moreover, an ultralow potential of 1.6 V was required to deliver a current density of 10 mA cm−2 in the two-electrode configuration for overall water splitting. For practical applications, intermittent solar energy, wind energy and thermal energy were utilized to drive the electrolyzer to generate hydrogen gas. This work provides a novel and facile strategy for designing highly efficient and stable nanomaterials toward hydrogen production.


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