Screening and Understanding Lattice Silicon‐Controlled Catalytically Active Site Motifs from a Library of Transition Metal‐Silicon Intermetallics

Abstract

A joint theoretical and experimental study is reported to systematically explore over a library of transition metal‐silicon intermetallics for understanding silicon‐controlled active site motifs and discovering hydrogen‐evolving electrocatalysts. On the one hand, every low‐index surface termination of 115 transition metal (M)‐silicon (Si) intermetallics is enumerated, followed by cataloging of stable adsorption sites and prediction of catalytic activities on the main exposed facets. It is theoretically found that silicon atoms in silicon‐rich structures (especially MSi2 and MSi) show a strong site‐isolating effect, which can eliminate M‐M‐M hollow and M‐M bridge sites with too strong hydrogen‐binding ability and thereby provide great opportunities for the exposure of novel highly active sites (e.g., M‐top and Si‐related sites). On the other hand, solid‐state redox reactions are developed to synthesize a set of 24 silicides containing 5 MSi, 13 MSi2, and 6 others, most of which are phase‐pure samples. The experimental studies demonstrate that too rich silicon content in silicides (e.g., MSi2) leads to adverse effects, such as the formation of amorphous SiOx layers on the silicide surface, masking the presence of active sites during electrocatalysis. Finally, 5 MSi (M = Rh, Pd, Pt, Ru, Ir) as highly active hydrogen‐evolving electrocatalysts are identified.

d–sp orbital hybridization: a strategy for activity improvement of transition metal catalysts

“…Many other metals/metalloids in the p-block group easily form structurally ordered intermetallics with transition metals. [84][85][86] Our group theoretically studied a series of intermetallics of RuX (X = Si, Ge, Sn, Al, Ga and In). 87 We found that the activity of these Ru top sites was closely related to the d-band center (Fig.…”

Production of complex Fe-Si-Mn-Cr ferroalloy using high-ash coal: a sustainable metallurgical approach

“…The reduction of metallic Fe and Mn promotes the reduction of Si, because these metals reduce the activity and activity coefficient of Si within the alloy and facilitate the formation of silicides, thereby impacting the reduction process. The affinity of Si for forming silicides with metals in the ferroalloy follows the sequence Mn > Fe > Cr, based on the standard change in Gibbs free energy associated with the formation of the respective silicides [17,18]. Cr, by dissolving up to 70% Mn in the solid state, reduces Mn's activity and enhances the reduction process [2].…”

Inorganic non-carbon supported Pt catalysts and synergetic effects for oxygen reduction reaction

“…Silicon oxides are commonly considered as passive layers in electrocatalytic systems, but their stability also suggests their potential as support materials. 100 In addition, the SiO 2 support may also catalytically induce loading processes. 101 In general, silicon oxides and tin oxides have similar insolubility and chemical inertness properties.…”