Metal support effects in electrocatalysis at hexagonal boron nitride

Liu, Dan-Qing; Tao, Binglin; Ruan, Hongcheng; Bentley, Cameron Luke; Unwin, Patrick R.

doi:10.1039/c8cc08517j

Cited by 45 publications

(42 citation statements)

References 38 publications

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“…The invention of the scanning tunnelling microscope (STM) had a significant impact on the study of electrochemical interfaces and further led to the development of electrochemically‐based scanned probe microscopes (SPMs) . Scanning electrochemical probe microscopes (SEPMs), which use a small electrode or electrochemical half‐cell as a probe (tip), have attracted considerable attention as a means of mapping electrochemical activity and chemical fluxes at the microscale and nanoscale for a wide range of substrates and materials . While the spatiotemporal resolution of SEPM has improved over the years, the ultimate lateral resolution of these methods is generally limited by either diffusion of the measured species to the electrode (diffusional blur) and/or the physical size of the tip used…”

Section: Introductionmentioning

confidence: 99%

“…[2][3][4][5][6][7][8][9] Scanning electrochemical probe microscopes (SEPMs), which use a small electrode or electrochemical half-cell as a probe (tip), have attracted considerable attention as a means of mapping electrochemical activity and chemical fluxes at the microscale and nanoscale for a wide range of substrates and materials. [3][4][5][10][11][12][13][14][15][16] While the spatiotemporal resolution of SEPM has improved over the years, the ultimate lateral resolution of these methods is generally limited by either diffusion of the measured species to the electrode (diffusional blur) and/or the physical size of the tip used. [17] A well-known problem of some SEPMs, like scanning electrochemical microscopy (SECM), is that the tip response depends on both surface activity and tip-substrate distance.…”

Section: Introductionmentioning

confidence: 99%

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Synchronous Electrical Conductance‐ and Electron Tunnelling‐Scanning Electrochemical Microscopy Measurements

et al. 2020

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The requirement to separate topographical effects from surface electrochemistry information is a major limitation of scanning electrochemical microscopy (SECM). With many applications of SECM involving the study of (semi)conducting electrode surfaces, the hybridisation of SECM with scanning tunnelling microscopy (STM) or a surface conductance probe would provide the ultimate topographical imaging capability to SECM, but previous attempts are limited. Here, the conversion of a general scanning electrochemical probe microscopy (SEPM) platform to facilitate contact electrical conductance (C)‐ and electron tunnelling (T)‐SECM measurements is considered. Measurements in air under ambient conditions with a Pt/Ir wire tip are used to assess the performance of the piezoelectric positioning system. A hopping‐mode imaging protocol is implemented, whereby the tip approaches the surface at each pixel until a desired current magnitude is exceeded, and the corresponding z position (surface height) is recorded at a set of predefined xy coordinates in the plane of the surface. At slow tip approach rates, the current shows an exponential dependence on tip‐substrate distance, as expected for electron tunnelling. For measurements in electrochemical environments, in order to overcome well‐known problems with leakage currents at coated‐wire tips used for electrochemical STM, Pt‐sensitised carbon nanoelectrodes are used as tips. The hydrogen evolution reaction on 2D Au nanocrystals serves as an exemplar system for the successful simultaneous mapping of topography and electrochemical activity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synchronous Electrical Conductance‐ and Electron Tunnelling‐Scanning Electrochemical Microscopy Measurements

et al. 2020

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“…However, Liu et al studied h-BN supported on Au and Cu (h-BN/Au and h-BN/Cu) by scanning electrochemical droplet cell technique. Obtained results revealed improvement but still a very poor activity of h-BN on Cu and moderate activity of h-BN/Au (two orders of magnitude higher than for h-BN/Cu), which revealed a significant influence of the metallic surface [72].…”

Section: Supported Metallic Nanoparticlesmentioning

confidence: 93%

Hydrogen Evolution Reaction-From Single Crystal to Single Atom Catalysts

et al. 2020

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Hydrogen evolution reaction (HER) is one of the most important reactions in electrochemistry. This is not only because it is the simplest way to produce high purity hydrogen and the fact that it is the side reaction in many other technologies. HER actually shaped current electrochemistry because it was in focus of active research for so many years (and it still is). The number of catalysts investigated for HER is immense, and it is not possible to overview them all. In fact, it seems that the complexity of the field overcomes the complexity of HER. The aim of this review is to point out some of the latest developments in HER catalysis, current directions and some of the missing links between a single crystal, nanosized supported catalysts and recently emerging, single-atom catalysts for HER.

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“…However, Liu et al studied h-BN supported on Au and Cu (h-BN/Au and h-BN/Cu) by scanning electrochemical droplet cell technique. Obtained results revealed improved, but yet a very poor activity of h-BN on Cu, and moderate activity of h-BN/Au (two orders of magnitude higher than for h-BN/Cu), which revealed a significant influence of the metallic surface [59].…”

Section: Supported Metallic Nanoparticlesmentioning

confidence: 95%

Hydrogen Evolution Reaction - From Single Crystal to Single Atom Catalysts

Gutić¹,

Dobrota²,

Fako³

et al. 2020

Preprint

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Hydrogen evolution reaction (HER) is one of the most important reaction in electrochemistry. This is not only because it is the simplest way to produce high purity hydrogen and the fact that it is the side reaction in many other technologies. HER actually shaped current electrochemistry because it was in focus of active research for so many years (and it still is). The number of catalysts investigated for HER is immense, and it is impossible to overview them all. In fact, it seems that the complexity of the field overcomes the complexity of HER. The aim of this review is to point out some of the latest developments in HER catalysis, current directions and some of the missing links between a single crystal, nanosized supported catalysts and, recently emerging, single atom catalysts for HER.3 of 36 HER at single crystal surfaces and bulk surfacesA crystalline solid can be considered as a series of mutually parallel lattice planes, arranged in a periodic way. Close to the surface, the spatial arrangement of the lattice planes, their crystallographic structure, as well as the dynamics of the constituent atoms may differ from the corresponding features in the bulk [1]. Most clean metals show the tendency to minimize their surface energy. One of the mechanisms is relaxation, the shift of one or more lattice planes located near to the surface, usually perpendicularly to the surface, so that the interlayer distance changes compared to the bulk lattice. The other one is reconstruction -change in equilibrium positions and bonding of surface atoms so that the projection of bulk unit cell to the given surface does not correspond to the surface unit cell. Different crystallographic planes (with different Miller indices) of the same metal exhibit unequal surface densities (number of atoms per surface area), and therefore undergo surface relaxation/reconstruction to different extents [2]. For example, Pt(100) has lower surface density compared to densely packed Pt(111) and therefore has a stronger tendency to relax/reconstruct. Since the main driving force for the mentioned surface modifications is the low coordination number (non-saturation) of surface atoms, it is obvious that atom/molecule adsorption on clean metal surfaces can have a significant effect on its surface structure, inducing relaxation/reconstruction changes. This is of huge importance for HER, as it involves adsorbed atomic hydrogen (Hads) as an intermediate. Additionally, in an electrochemical system, the electrode will be modified by adsorption of "spectator" species (ions/molecules from the electrolyte), so HER will not be taking place on clean metal surfaces, but rather on modified ones. Obviously, there is a complex dynamic interplay between the catalyst surface, reactants, intermediates, and electrolyte.According to the Sabatier principle, the interaction of the reaction reactants/intermediates with the catalyst has to be optimal in strength. If it is too weak, the reactants will not bind to the catalyst and the reaction will not be able to take place. In...

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Metal support effects in electrocatalysis at hexagonal boron nitride

Abstract: The metal support of hexagonal boron nitride nanosheets has a significant effect on the electrocatalytic hydrogen evolution reaction, as visualized by scanning electrochemical cell microscopy.

Cited by 45 publications

References 38 publications

Synchronous Electrical Conductance‐ and Electron Tunnelling‐Scanning Electrochemical Microscopy Measurements

Synchronous Electrical Conductance‐ and Electron Tunnelling‐Scanning Electrochemical Microscopy Measurements

Hydrogen Evolution Reaction-From Single Crystal to Single Atom Catalysts

Hydrogen Evolution Reaction - From Single Crystal to Single Atom Catalysts

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