Rational construction of Au–Ag bimetallic island-shaped nanoplates for electrocatalysis

Abstract

Active electrocatalysts are the key to water splitting for hydrogen production through the electrolysis. In this paper, 50 nm silver nanoplates were used as templates for synthesis of Au-Ag island-shaped nanoplates by controlling the surface chemistry. The guiding mechanism of polyvinylpyrrolidone (PVP, Mw=40 000) to Au-Ag island-shaped nanoplates crystal was also further investigated. It is found that the surface energy of Ag nanoplates between (100) and (111) crystal planes can be regulated by varying the amount of PVP in the system. Then a uniform Au-Ag triangular island nanostructure was obtained. Compared with the Ag nanoplates catalysts, the Au-Ag island nanoplates catalysts show the superior catalytic performances in hydrogen evolution electrocatalysis (HER). These results demonstrate a new surface chemistry modification by PVP and a galvanic displacement reaction for designing the active electrocatalysts. More importantly, the Au-Ag island-shaped nanoplates show an unconventional growth mode of preserving the original Ag nano-triangular crystal structure. The enhanced performance in electrocatalysis can be mainly attributed to Au-Ag alloy structure, which allows the appearance of synergistic effects. The present work demonstrates the crucial roles of surface chemistry in catalysts synthesis, which may guide the design of active bimetallic catalysts.

Effect of BN or B4C content on physical and tribological properties of copper‐clad laminates reinforced with carbon fiber and epoxy resin

“…This leads to more frequent and intense contact between the surfaces, resulting in higher friction and an increased coefficient of friction. [36][37][38] When BN or B 4 C particles are added, they can act as lubricants or protective agents between the surfaces, reducing direct metal-to-metal contact and friction. At an optimal particle content, the particles effectively fill surface defects, aid in smooth sliding, and reduce friction, resulting in a lower coefficient of friction.…”

Adsorption and solar light activity of noble metal adatoms (Au and Zn) on Fe(111) surface: a first-principles study

“…47 Their study intricately elucidated the atomic arrangements of these single-layer metal nanoislands on Au(111), providing comprehensive insights into their geometric, energetic, and electronic attributes. Other works have also reported that Pd or Pt on Au(111) commonly forms single-layer nanoislands, [33][34][35][36][37][38][39][40][41][42][43][44][48][49][50][51][52][53] while explorations have also extended to investigating bimetallic nanoislands, such as Ni/Au, [54][55][56][57][58][59] Cu/Au, [60][61][62][63][64] Rh/Au, [65][66][67][68][69][70] Pd-Rh/Au, 71 Ag/Au, 72,73 Ir/Au, 52 Au-Ag, 74 Ir/Ni, 52 Ag/Cu, 75 Rh/Pd, 76 Pd/Pt, 45 Ir/Pt, 52 and Pt/Cu. 77 In the present study, we conducted a thoro...…”