P doped Co2Mo3Se nanosheets grown on carbon fiber cloth as an efficient hybrid catalyst for hydrogen evolution

2017 ◽  
Vol 5 (24) ◽  
pp. 12043-12047 ◽  
Author(s):  
Yaxiao Guo ◽  
Zhaoyang Yao ◽  
Changshuai Shang ◽  
Erkang Wang

Owing to the prominent synergistic effects, P-Co2Mo3Se/CFC hybrid catalyst exhibits a superior HER activity with a small overpotential of 71 mV at cathodic current density of 10 mA cm−2, and a small Tafel slope of 43.6 mV dec−1, as well as excellent cycling stability.

2020 ◽  
Vol 10 (15) ◽  
pp. 5155 ◽  
Author(s):  
Dinesh Bhalothia ◽  
Sheng-Po Wang ◽  
Shuan Lin ◽  
Che Yan ◽  
Kuan-Wen Wang ◽  
...  

The development of inexpensive and highly robust nanocatalysts (NCs) to boost electrochemical hydrogen evolution reaction (HER) strengthens the implementation of several emerging sustainable-energy technologies. Herein, we proposed a novel nano-architecture consisting of a hierarchical structured Ni@Pd nanocatalyst with Pt-clusters decoration on the surface (denoted by Ni@Pd-Pt) for HER application in acidic (0.5 M H2SO4) and alkaline (0.1 M KOH) mediums. The Ni@Pd-Pt NC is fabricated on a carbon black support via a “self-aligned” heterogeneous nucleation-crystal growth mechanism with 2 wt.% Pt-content. As-prepared Ni@Pd-Pt NC outperforms the standard Pt/C (30 wt.% Pt) catalyst in HER and delivers high-rate catalytic performance with an ultra-low overpotential (11.5 mV) at the cathodic current density of 10 mA∙cm−2 in alkaline medium, which is 161.5 mV and 14.5 mV less compared to Ni@Pd (173 mV) and standard Pt/C (26 mV) catalysts, respectively. Moreover, Ni@Pd-Pt NC achieves an exactly similar Tafel slope (42 mV∙dec−1) to standard Pt/C, which is 114 mV∙dec−1 lesser when compared to Ni@Pd NC. Besides, Ni@Pd-Pt NC exhibits an overpotential value of 37 mV at the current density of 10 mA cm−2 in acidic medium, which is competitive to standard Pt/C catalyst. By utilizing physical characterizations and electrochemical analysis, we demonstrated that such an aggressive HER activity is dominated by the increased selectivity during HER due to the reduced competition between intermediate products on the non-homogeneous NC surface. This phenomenon can be rationalized by electron localization owing to the electronegative difference (χPt > χPd > χNi) and strong lattice mismatch at the Ni@Pd heterogeneous binary interfaces. We believe that the obtained results will significantly provide a facile design strategy to develop next-generation heterogenous NCs for HER and related green-energy applications


2019 ◽  
Vol 55 (65) ◽  
pp. 9665-9668 ◽  
Author(s):  
Quan Zhang ◽  
Fang Luo ◽  
Hao Hu ◽  
Ruizhi Xu ◽  
Konggang Qu ◽  
...  

W/W2C heterostructured nanoparticles encapsulated by N,P dual-doped carbon require low overpotentials of 55 mV and 82 mV vs. RHE to achieve cathodic current density of 10 mA cm−2 in acidic and alkaline electrolytes, respectively.


RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90265-90271 ◽  
Author(s):  
Lili Li ◽  
Xingyue Li ◽  
Lunhong Ai ◽  
Jing Jiang

Zeolitic imidazolate framework-67 derived nanostructured CoP assemblies exhibited high-performance for electrochemical HER, as manifested by a low overpotential, a large cathodic current density and an excellent durability.


2019 ◽  
Vol 55 (15) ◽  
pp. 2186-2189 ◽  
Author(s):  
Alpesh K. Sharma ◽  
Hemant Joshi ◽  
Kasinath Ojha ◽  
Ajai K. Singh

The cathodic current density (cd) of GO-Co2P is 20/100 mA cm−2 at an overpotential of 80/154 mV. At 100 mA cm−2 cd, stability is observed for 70 h.


2015 ◽  
Vol 3 (11) ◽  
pp. 5783-5788 ◽  
Author(s):  
Kai Zhang ◽  
Yang Zhao ◽  
Diyu Fu ◽  
Yujin Chen

Highly conductive N-doped carbon nanotubes embedded with molybdenum carbide nanocrystals with a size less than 3 nm exhibit superior activity for the hydrogen evolution reaction, including small overpotential, large cathodic current density and high exchange current density.


CORROSION ◽  
2012 ◽  
Vol 68 (4) ◽  
pp. 045003-1-045003-10 ◽  
Author(s):  
M. Akhoondan ◽  
A.A. Sagüés

The extent of the oxygen reduction reaction in concrete was evaluated for ~9% Cr rebar approaching the ASTM A1035 specification and compared to that of conventional carbon steel rebar, at ages of up to ~1 year. Cathodic strength was measured by the cathodic current density developed at −0.35 V vs. copper/copper sulfate (Cu/CuSO4 [CSE]) and −0.40 VCSE in cyclic cathodic potentiodynamic polarization tests, both in the as-received condition with mill scale and with scale removed by glass bead surface blasting. In both conditions the ~9% Cr alloy was a substantially weaker cathode, by a factor of several fold, than carbon steel. Within each material, the surface-blasted condition yielded also much lower cathodic current density than the as-received condition. For a small anode-large cathode system with a given anode polarization function, and no important oxygen reduction concentration polarization, the corrosion current was projected to be significantly lower if the cathodic region were ~9% Cr instead of plain steel rebar with comparable surface condition. There was strong correlation between the charge storage capability of the interface and the extent of cathodic reaction of oxygen. The result cannot be ascribed solely to differences in effective surface area between the different materials and conditions.


2015 ◽  
Vol 180 ◽  
pp. 313-330 ◽  
Author(s):  
Geraint Williams ◽  
Nick Birbilis ◽  
H. Neil McMurray

The early stages of localised corrosion affecting magnesium (Mg) surfaces when immersed in aqueous sodium chloride (NaCl) solutions involves the propagation of dark regions, within which both anodic metal dissolution and cathodic hydrogen evolution occur. For nominally “pure” Mg, these dark areas can either take the form of discs which expand radially with time, or filiform-like tracks which lengthen with time. For Mg surfaces which display disc-form corrosion features in concentrated NaCl electrolyte, a transition to filiform corrosion (FFC) is observed as the concentration is decreased, indicating ohmic constraints on radial propagation. A similar effect is observed when Mg specimens of different iron impurity are immersed in a fixed, high concentration NaCl solution, where disc-form corrosion is observed on samples having ≥280 ppm Fe, but FFC predominates at ≤80 ppm Fe. An in situ scanning vibrating electrode technique (SVET) is used to determine current density distributions within the propagating corrosion features. Cathodic current density values of between −100 and −150 A m−2 measured in central areas of disc-like features are sufficient to sustain the radial growth of a local anode at the perimeter of the discs. However, for high purity Mg specimens (≤80 ppm Fe), cathodic current densities of −10 A m−2 or less are measured over FFC affected regions, indicating that linear propagation arises when there is insufficient cathodic current produced on the corroded surface to sustain radial growth. The results are consistent with surface control of localised corrosion propagation in concentrated electrolyte, but ohmic control in dilute, lower conductivity NaCl solution.


2018 ◽  
Vol 775 ◽  
pp. 139-143 ◽  
Author(s):  
Luigi A. Dahonog ◽  
Mary Donnabelle L. Balela

Nickel cobaltite (NiCo2O4) nanowires were successfully grown on the surface of carbon fiber via hydrothermal treatment, followed by annealing. After 2 h, SEM revealed the formation of NiCo2O4 nanowire arrays on the surface of the carbon fiber paper. With increasing hydrothermal time from 2 to 12 h, the NiCo2O4 nanowires also self-assembled into urchin-like morphologies. When used as catalysts for hydrogen evolution reaction, the NiCo2O4 nanowires exhibit an onset potential for the cathodic current at-0.13 V vs. Ag/AgCl in 0.1 M KOH.


2019 ◽  
Vol 3 (12) ◽  
pp. 3344-3351 ◽  
Author(s):  
Pei Liu ◽  
Yibin Lu ◽  
Wenjun Ma ◽  
Linzheng Ma ◽  
Qingyun Liu ◽  
...  

Cerium and nitrogen co-doped CoP nanorod arrays on carbon fiber cloth were developed as pH-universal HER electrocatalyst with the low overpotentials of 66 mV, 72 mV, and 41 mV at 10 mA cm−2 in 0.5 M H2SO4, 1 M PBS, and 1 M KOH, respectively.


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