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An amorphous Co–Mo–B film on a Ti mesh (Co–Mo–B/Ti) is fabricated via one-step electrodeposition exhibiting a dramatically enhanced hydrogen evolution reaction (HER) performance in alkaline media. To attain a current density of 20 mA cm−2, such Co–Mo–B/Ti demands only an overpotential of 110 mV, 190 mV lower than that of the counterpart Co–B/Ti, with strong electrochemical durability to maintain its catalytic activity for at least 32 h. [ABSTRACT FROM AUTHOR]

Abstract: Cost‐effective and highly‐efficient electrocatalysts for the oxygen evolution reaction are crucial for electrolytic hydrogen production. Here, we report core–shell NiO@Ni‐P nanosheet arrays as a high‐performance 3D catalyst for water oxidation electrocatalysis. Such nanoarrays demand overpotentials of 292 and 350 mV to drive geometrical catalytic current densities of 10 and 100 mA cm−2, respectively, with an activity superior to its NiO and Ni‐P counterparts. Notably, this catalyst also shows a high long‐term electrochemical durability with a Faradaic efficiency of 98.1 %. Density functional theory calculation reveals that the superior activity benefits from the synergistic effect between NiO and Ni‐P. [ABSTRACT FROM AUTHOR]

Exploitation of efficient and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is of great importance. Herein, we report that the formation of an amorphous Mn–Co–P shell on MnCo2O4 can boost its OER activity in alkaline media. The core–shell Mn–Co–P@MnCo2O4 nanowire array on Ti mesh (Mn–Co–P@MnCo2O4/Ti) shows excellent electrochemical catalytic activity and requires an overpotential of 269 mV to drive 10 mA cm−2 in 1.0 M KOH, which is 93 mV less than that for the MnCo2O4 nanoarray. Notably, this catalyst also shows strong long-term electrochemical durability with its activity being maintained for at least 100 h and achieves a high turnover frequency of 1.06 s−1 at an overpotential of 450 mV. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop a simple, fast and straightforward method to boost the alkaline water oxidation of metal oxide catalysts. In this communication, we report our recent finding that the generation of amorphous Co-borate layer on Co3O4 nanowire arrays supported on Ti mesh (Co3O4@Co-Bi NA/TM) leads to significantly boosted OER activity. The as-prepared Co3O4@Co-Bi NA/TM demands overpotential of 304 mV to drive a geometrical current density of 20 mA cm-2 in 1.0 M KOH, which is 109 mV less than that for Co3O4 NA/TM, with its catalytic activity being preserved for at least 20 h. It suggests that the existence of amorphous Co-Bi layer promotes more CoOx(OH)y generation on Co3O4 surface. [ABSTRACT FROM AUTHOR]

Environmentally friendly electrochemical hydrogen production needs the development of earth-abundant catalyst materials for the hydrogen evolution reaction with high activity and durability at neutral pH. In this work, the self-templating construction of a hollow amorphous CoMoS4 nanotube array on carbon cloth (CoMoS4 NTA/CC) is reported, using hydrothermal treatment of a Co(OH)F nanowire array on CC in (NH4)2MoS4 solution. When used as a 3D electrode for hydrogen evolution electrocatalysis, the resulting CoMoS4 NTA/CC demonstrates superior catalytic activity and strong long-term electrochemical durability in 1.0 M phosphate buffer solution (pH=7). It shows small onset overpotential of 21 mV and requires low overpotentials of 104 and 179 mV to drive geometrical current densities of 10 and 50 mA cm−2, respectively. Density functional theory calculations suggest that CoMoS4 has a more favorable hydrogen adsorption free energy than Co(OH)F. [ABSTRACT FROM AUTHOR]

Searching for a simple and fast strategy to effectively enhance the oxygen evolution reaction (OER) performance of non-noble-metal electrocatalysts in alkaline media remains a significant challenge. Herein, the OER activity of NiFe-LDH nanoarray on carbon cloth (NiFe-LDH/CC) in alkaline media is shown to be greatly boosted by an amorphous NiFe-Borate (NiFe-Bi) layer formation on NiFe-layered double hydroxide (NiFe-LDH) surface. Such a NiFe-LDH@NiFe-Bi/CC catalyst electrode only needs an overpotential of 294 mV to drive 50 mA cm−2 in 1.0 m KOH; 116 mV less than that needed by NiFe-LDH/CC. Notably, this electrode also demonstrates strong long-term electrochemical durability. The superior activity is ascribed to the pre-formed amorphous NiFe-Bi layer effectively promoting active species generation on the NiFe-LDH surface. This work opens up exciting new avenues for developing high-performance water-oxidation catalyst materials for application. [ABSTRACT FROM AUTHOR]

The development of high-performance and cost-effective water oxidation catalysts operating under mild conditions is attractive for the conversion of electricity into chemical fuels. In this communication, we report the in situ electrochemical development of a Ni-Bi layer (5-8 nm thick) on a NiS2 nanoarray supported on carbon cloth (i.e., NiS2@Ni-Bi/CC) for efficient water oxidation in 0.1 m potassium borate electrolyte at pH 9.2. As a durable 3 D catalyst electrode, core-shell-structured NiS2@Ni-Bi/CC shows excellent catalytic activity for water oxidation and approaches a geometrical catalytic current density of 20 mA cm−2 at an overpotential of 486 mV, with long-term electrochemical stability for at least 24 h with a high turnover frequency of 0.28 mol O2 s−1 at an overpotential of 500 mV and nearly 100 % Faradic efficiency for oxygen evolution. [ABSTRACT FROM AUTHOR]

As a non-toxic species, Zn fulfills a multitude of biological roles, but its promoting effect on electrocatalysis has been rarely explored. Herein, the theoretic predications and experimental investigations that nonelectroactive Zn behaves as an effective promoter for CoP-catalyzed hydrogen evolution reaction (HER) in both acidic and alkaline media is reported. Density function theory calculations reveal that Zn doing leads to more thermal-neutral hydrogen adsorption free energy and thus enhanced HER activity for CoP catalyst. Electrochemical tests show that a Zn0.08Co0.92P nanowall array on titanium mesh (Zn0.08Co0.92P/TM) needs overpotentials of only 39 and 67 mV to drive a geometrical catalytic current of 10 mA cm-2 in 0.5 m H2SO4 and 1.0 m KOH, respectively. This Zn0.08Co0.92P/TM is also superior in activity over CoP/TM for urea oxidation reaction (UOR), driving 115 mA cm-2 at 0.6 V in 1.0 m KOH with 0.5 m urea. The high HER and UOR activity of this bifunctional electrode enables a Zn0.08Co0.92P/TM-based two-electrode electrolyzer for energy-saving hydrogen production, offering 10 mA cm-2 at a low voltage of 1.38 V with strong long-term electrochemical stability. [ABSTRACT FROM AUTHOR]

Nickel-borate nanosheets array on titanium mesh (Ni−Bi NA/TM) was derived from NiSe2 nanosheets array on titanium mesh (NiSe2 NA/TM) by electrochemical transformation. As a three-dimensional electrode, Ni−Bi NA/TM exhibited high catalytic activity toward the oxygen evolution reaction and required a low overpotential of 430 mV at 10 mA cm−2 in 0.1 m potassium borate (pH 9.2), with outstanding long-term stability and high turnover frequency. [ABSTRACT FROM AUTHOR]