scholarly journals Accelerating water dissociation in bipolar membranes and for electrocatalysis

Science ◽  
2020 ◽  
Vol 369 (6507) ◽  
pp. 1099-1103 ◽  
Author(s):  
Sebastian Z. Oener ◽  
Marc J. Foster ◽  
Shannon W. Boettcher
Keyword(s):  
Metal Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Pure Water ◽  
Proton Exchange ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Bipolar Membranes ◽  
Exchange Layer ◽  
Acidic Proton

Catalyzing water dissociation (WD) into protons and hydroxide ions is important both for fabricating bipolar membranes (BPMs) that can couple different pH environments into a single electrochemical device and for accelerating electrocatalytic reactions that consume protons in neutral to alkaline media. We designed a BPM electrolyzer to quantitatively measure WD kinetics and show that, for metal nanoparticles, WD activity correlates with alkaline hydrogen evolution reaction activity. By combining metal-oxide WD catalysts that are efficient near the acidic proton-exchange layer with those efficient near the alkaline hydroxide-exchange layer, we demonstrate a BPM driving WD with overpotentials of <10 mV at 20 mA·cm−2 and pure water BPM electrolyzers that operate with an alkaline anode and acidic cathode at 500 mA·cm−2 with a total electrolysis voltage of ~2.2 V.

Tungsten-doped Ni–Co phosphides with multiple catalytic sites as efficient electrocatalysts for overall water splitting

2019 ◽  
Vol 7 (28) ◽  
pp. 16859-16866 ◽  
Author(s):  
Shan-Shan Lu ◽  
Li-Ming Zhang ◽  
Yi-Wen Dong ◽  
Jia-Qi Zhang ◽  
Xin-Tong Yan ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydrogen Evolution Reaction ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Overall Water Splitting ◽  
Catalytic Sites ◽  
Additional Water ◽  
Dissociation Step

The design of electrocatalysts including precious and nonprecious metals for the hydrogen evolution reaction (HER) in alkaline media remains challenging due to the sluggish reaction kinetics caused by the additional water dissociation step.

scholarly journals Facile Synthesis of PdCuRu Porous Nanoplates as Highly Efficient Electrocatalysts for Hydrogen Evolution Reaction in Alkaline Medium

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1451
Author(s):  
Changhong Chen ◽  
Ningkang Qian ◽  
Junjie Li ◽  
Xiao Li ◽  
Deren Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Alkaline Solution ◽  
Current Density ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Galvanic Replacement ◽  
Facile Synthesis ◽  
Better Than

Ru is a key component of electrocatalysts for hydrogen evolution reaction (HER), especially in alkaline media. However, the catalytic activity and durability of Ru-based HER electrocatalysts are still far from satisfactory. Here we report a solvothermal approach for the synthesis of PdCuRu porous nanoplates with different Ru compositions by using Pd nanoplates as the seeds. The PdCuRu porous nanoplates were formed through underpotential deposition (UPD) of Cu on Pd, followed by alloying Cu with Pd through interdiffusion and galvanic replacement between Cu atoms and Ru precursor simultaneously. When evaluated as HER electrocatalysts, the PdCuRu porous nanoplates exhibited excellent catalytic activity and durability. Of them, the Pd24Cu29Ru47/C achieved the lowest overpotential (40.7 mV) and smallest Tafel slope (37.5 mV dec−1) in an alkaline solution (much better than commercial Pt/C). In addition, the Pd24Cu29Ru47/C only lost 17% of its current density during a stability test for 10 h, while commercial Pt/C had a 59.5% drop under the same conditions. We believe that the electron coupling between three metals, unique porous structure, and strong capability of Ru for water dissociation are responsible for such an enhancement in HER performance.

scholarly journals Industry-applicable, efficient hydrogen evolution reaction through an interface-activated bimetallic electrode with seawater photolysis in alkaline media

2020 ◽  
Author(s):  
Ashwani Kumar ◽  
Viet Quoc Bui ◽  
Jinsun Lee ◽  
Amol R. Jadhav ◽  
Yoseph Whang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Theoretical Calculations ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Hydrogen Economy ◽  
Active Electrode ◽  
Cu Nanowires ◽  
Adsorption Free Energy ◽  
Exceptional Stability

<p><a><b>Hydrogen evolution reaction (HER) electrocatalysts over platinum (Pt) in an alkaline medium is crucial for hydrogen economy. Herein, we demonstrate new concept “interface-active electrode” to transform naturally inert alkaline HER materials towards industry-applicable HER electrocatalyst, comprised of interface-rich NiP<sub>2</sub>-FeP<sub>2</sub> on Cu nanowires that required overpotential as low as 23.6 and 357 mV at -10 and -1000 mA/cm<sup>2</sup>, respectively, with exceptional stability at the industrial current density of -1 A cm<sup>-2</sup>, superior to commercial Pt under alkaline solution. Structural characterization and theoretical calculations revealed the abundant interface between facets of NiP<sub>2</sub>-FeP<sub>2 </sub>on Cu exhibits optimum H adsorption-free energy than Pt and lower kinetic barrier for water dissociation (Δ<i>G</i><sub>B</sub> = 0.16 eV), boosting alkaline HER. Additionally, when integrated in a water splitting device, generated 10 mA/cm<sup>2 </sup>at only </b></a><b>1.42, 1.4, and 1.31 V </b><b>under 1 M KOH, artificial seawater at 25 ̊C and 100 ̊C, respectively, along with high solar-to-hydrogen (STH) conversion efficiency of 19.85</b><b> %. </b></p>

scholarly journals Industry-applicable, efficient hydrogen evolution reaction through an interface-activated bimetallic electrode with seawater photolysis in alkaline media

2020 ◽  
Author(s):  
Ashwani Kumar ◽  
Viet Quoc Bui ◽  
Jinsun Lee ◽  
Amol R. Jadhav ◽  
Yoseph Whang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Theoretical Calculations ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Hydrogen Economy ◽  
Active Electrode ◽  
Cu Nanowires ◽  
Adsorption Free Energy ◽  
Exceptional Stability

<p><a><b>Hydrogen evolution reaction (HER) electrocatalysts over platinum (Pt) in an alkaline medium is crucial for hydrogen economy. Herein, we demonstrate new concept “interface-active electrode” to transform naturally inert alkaline HER materials towards industry-applicable HER electrocatalyst, comprised of interface-rich NiP<sub>2</sub>-FeP<sub>2</sub> on Cu nanowires that required overpotential as low as 23.6 and 357 mV at -10 and -1000 mA/cm<sup>2</sup>, respectively, with exceptional stability at the industrial current density of -1 A cm<sup>-2</sup>, superior to commercial Pt under alkaline solution. Structural characterization and theoretical calculations revealed the abundant interface between facets of NiP<sub>2</sub>-FeP<sub>2 </sub>on Cu exhibits optimum H adsorption-free energy than Pt and lower kinetic barrier for water dissociation (Δ<i>G</i><sub>B</sub> = 0.16 eV), boosting alkaline HER. Additionally, when integrated in a water splitting device, generated 10 mA/cm<sup>2 </sup>at only </b></a><b>1.42, 1.4, and 1.31 V </b><b>under 1 M KOH, artificial seawater at 25 ̊C and 100 ̊C, respectively, along with high solar-to-hydrogen (STH) conversion efficiency of 19.85</b><b> %. </b></p>

scholarly journals Tailoring Water Dissociation Energy by Platinum Single-Atom Catalyst Coupled with Transition Metal/metal Oxide Heterostructure for Accelerating Alkaline Hydrogen Evolution Reaction

2021 ◽  
Author(s):  
Changbao Han ◽  
Kailing Zhou ◽  
Qianqian Zhang ◽  
Jingbing Liu ◽  
Hui Yan ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Dissociation Energy ◽  
Active Sites ◽  
Alkaline Media ◽  
Water Dissociation ◽  
High Mass ◽  
Single Atom ◽  
Adsorption Affinity ◽  
Metal Metal

Abstract High-activity catalysts in alkaline media are compelling for durable hydrogen evolution reaction (HER). Single-atom catalysts (SACs) provide an effective approach to reduce the amount of precious metals meanwhile maintain their catalytic activity. However, the sluggish activity of SACs for water dissociation in alkaline media has extremely hampered advances in highly efficient hydrogen production. Herein, we developed a platinum SAC immobilized NiO/Ni heterostructure (PtSA-NiO/Ni) as an alkaline HER catalyst. It was found that Pt SACs coupled with NiO/Ni heterostructure enable the tunable binding abilities of hydroxyl ions (OH*) and hydrogen (H*), which efficiently tailors the water dissociation energy for accelerating alkaline HER. In particular, the dual active sites consisting of metallic Ni sites and O vacancies modified NiO sites near the interfaces of NiO/Ni in PtSA-NiO/Ni have preferred adsorption affinity for H* and OH* groups, respectively, which efficiently lowers the energy barrier of water dissociation of Volmer step. Moreover, anchoring Pt single atoms at the interfaces of NiO/Ni heterostructure induces more free electrons on Pt sites due to the elevated occupation of the Pt 5d orbital at the Fermi level and reaches a near-zero H binding energy (ΔGH*, 0.07 eV), which further promotes the H* conversion and H2 evolution. Further enhancement of alkaline HER performance was achieved by constructing PtSA-NiO/Ni nanosheets on the Ag nanowires to form a hierarchical three-dimensional (3D) morphology that provides abundant active sites and accessible channels for charge transfer and mass transport. Consequently, the fabricated PtSA-NiO/Ni catalyst displays extremely high alkaline HER performances with a quite high mass activity of 20.6 A mg-1 for Pt at the overpotential of 100 mV, which is 41 times greater than that of the commercial Pt/C catalyst, significantly outperforming the reported catalysts.

Surface Strain Engineered Ni-NiO for Boosting Hydrogen Evolution Reaction in Alkaline Media

2021 ◽  
pp. 138985
Author(s):  
Xuerui Yi ◽  
Xiaobo He ◽  
Fengxiang Yin ◽  
Guoru Li ◽  
Zhichun Li
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Surface Strain ◽  
Alkaline Media
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