scholarly journals Moving beyond bimetallic-alloy to single-atom dimer atomic-interface for all-pH hydrogen evolution

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ashwani Kumar ◽  
Viet Q. Bui ◽  
Jinsun Lee ◽  
Lingling Wang ◽  
Amol R. Jadhav ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Atomic Level ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Single Atom ◽  
Synthetic Strategy ◽  
Theoretical Predictions ◽  
Proton Adsorption ◽  
Acidic And Alkaline Media ◽  
Atomic Interface

AbstractSingle-atom-catalysts (SACs) afford a fascinating activity with respect to other nanomaterials for hydrogen evolution reaction (HER), yet the simplicity of single-atom center limits its further modification and utilization. Obtaining bimetallic single-atom-dimer (SAD) structures can reform the electronic structure of SACs with added atomic-level synergistic effect, further improving HER kinetics beyond SACs. However, the synthesis and identification of such SAD structure remains conceptually challenging. Herein, systematic first-principle screening reveals that the synergistic interaction at the NiCo-SAD atomic interface can upshift the d-band center, thereby, facilitate rapid water-dissociation and optimal proton adsorption, accelerating alkaline/acidic HER kinetics. Inspired by theoretical predictions, we develop a facile strategy to obtain NiCo-SAD on N-doped carbon (NiCo-SAD-NC) via in-situ trapping of metal ions followed by pyrolysis with precisely controlled N-moieties. X-ray absorption spectroscopy indicates the emergence of Ni-Co coordination at the atomic-level. The obtained NiCo-SAD-NC exhibits exceptional pH-universal HER-activity, demanding only 54.7 and 61 mV overpotentials at −10 mA cm−2 in acidic and alkaline media, respectively. This work provides a facile synthetic strategy for SAD catalysts and sheds light on the fundamentals of structure-activity relationships for future applications.

Ni3[Fe(CN)6]2 nanocubes boost the catalytic activity of Pt for electrochemical hydrogen evolution

2018 ◽  
Vol 5 (7) ◽  
pp. 1683-1689 ◽  
Author(s):  
Xiao Zhang ◽  
Pei Liu ◽  
Yanfang Sun ◽  
Tianrong Zhan ◽  
Qingyun Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Kinetics ◽  
Hydrogen Evolution ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Acidic And Alkaline Media ◽  
Ni Species ◽  
Low Pt Loading ◽  
Kinetics Of

Hybrid electrocatalyst of ultrafine Pt particles anchored on a Ni3[Fe(CN)6]2 nanocube with low Pt loading of 4.0% is designed for HERs, and superior catalytic activity is obtained in both acidic and alkaline media because the Ni species remarkably facilitates the reaction kinetics of water dissociation and thus improves HER activity.

scholarly journals Charge localized atomic Moδ+ site boosting hydrogen evolution in alkaline solution

2020 ◽  
Author(s):  
Maoqi Cao ◽  
Kang Liu ◽  
Yao Song ◽  
Chao Ma ◽  
Yiyang Lin ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Active Site ◽  
Density Functional ◽  
Alkaline Media ◽  
Water Dissociation ◽  
Single Atom ◽  
Alkaline Solutions ◽  
X Ray ◽  
Tafel Slope ◽  
Charge Localization

Abstract Electrochemical water splitting has drawn tremendous interest for the scalable and sustainable conversion of renewable electricity to clear hydrogen fuel and chemicals. However, the sluggishly kinetics of water dissociation step in alkaline solutions restrict severely the application of hydrogen evolution reaction (HER). Here, we designed and prepared cobalt layers with nitrogen modified atomically dispersed Mo sites (N-Mo/Co SAA) to boost the activity of HER. Density functional theory (DFT) calculations demonstrated that the N can induce the asymmetry charge localization of Moδ+ to facilitate the water dissociation. The energy barriers of water dissociation reduced from 0.48 to 0.35 eV by the charge localized Moδ+ site. High resolution transmission electron microscope (HRTEM) and synchrotron X-ray absorption spectroscopy (XAS) measurements confirmed the structure of N modified atomically dispersed Moδ+. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) measurements assessed the atomically dispersed Moδ+ site is the active site for water dissociation. Thus, the obtained N-Mo/Co catalyst exhibits record activity with 12 mV overpotential to achieve the current density of 10 mA cm− 2 and Tafel slope of 31 mV dec− 1 in alkaline media, which are superior to 32 mV overpotential for 10 mA cm− 2 and 38 mV dec− 1 Tafel slope on best commercial 20 wt% Pt/C sample in the same condition. This design strategy provided a new pathway to boost the activity of single atom alloy (SAA) by regulating the charge localization of the active site precisely at the atomic-level.

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.

scholarly journals Electronic metal–support interaction modulates single-atom platinum catalysis for hydrogen evolution reaction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Shi ◽  
Zhi-Rui Ma ◽  
Yi-Ying Xiao ◽  
Yun-Chao Yin ◽  
Wen-Mao Huang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Structure Activity Relationship ◽  
Atomic Level ◽  
Single Atom ◽  
Activity Relationship ◽  
Support Interaction ◽  
Structure Activity ◽  
Metal Support Interaction ◽  
Metal Support

AbstractTuning metal–support interaction has been considered as an effective approach to modulate the electronic structure and catalytic activity of supported metal catalysts. At the atomic level, the understanding of the structure–activity relationship still remains obscure in heterogeneous catalysis, such as the conversion of water (alkaline) or hydronium ions (acid) to hydrogen (hydrogen evolution reaction, HER). Here, we reveal that the fine control over the oxidation states of single-atom Pt catalysts through electronic metal–support interaction significantly modulates the catalytic activities in either acidic or alkaline HER. Combined with detailed spectroscopic and electrochemical characterizations, the structure–activity relationship is established by correlating the acidic/alkaline HER activity with the average oxidation state of single-atom Pt and the Pt–H/Pt–OH interaction. This study sheds light on the atomic-level mechanistic understanding of acidic and alkaline HER, and further provides guidelines for the rational design of high-performance single-atom catalysts.

Nanostructured molybdenum phosphide/N,P dual-doped carbon nanotube composite as electrocatalysts for hydrogen evolution

RSC Advances ◽  
2016 ◽  
Vol 6 (9) ◽  
pp. 7370-7377 ◽  
Author(s):  
Yang Zhao ◽  
Shuo Wang ◽  
Chunyan Li ◽  
Xianbo Yu ◽  
Chunling Zhu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hydrogen Evolution ◽  
Alkaline Media ◽  
Term Stability ◽  
Long Term Stability ◽  
Excellent Activity ◽  
Molybdenum Phosphide ◽  
Carbon Nanotube Composite ◽  
Acidic And Alkaline Media

MoP/N,P dual-doped carbon nanotube composite exhibited excellent activity and long-term stability toward HER both in acidic and alkaline media, superior to most of catalysts reported previously.

Sign in / Sign up

Export Citation Format

Share Document