Unexpected Correlation Between Boron Chain Condensation and Hydrogen Evolution Reaction (HER) Activity in Highly Active Vanadium Borides: Enabling Predictions

Abstract

Transition‐metal borides (TMBs) have recently attracted attention as excellent hydrogen evolution (HER) electrocatalysts in bulk crystalline materials. Herein, we show for the first time that VB and V3B4 have high electrocatalytic HER activity. Furthermore, we show that the HER activity (in 0.5 m H2SO4) increases with increasing boron chain condensation in vanadium borides: Using a −23 mV overpotential decrement derived from −0.296 mV (for VB at −10 mA cm−2 current density) and −0.273 mV (for V3B4) we accurately predict the overpotential of VB2 (−0.204 mV) as well as that of unstudied V2B3 (−0.250 mV) and hypothetical “V5B8” (−0.227 mV). We then derived an exponential equation that predicts the overpotentials of known and hypothetical VxBy phases containing at least a boron chain. These results provide a direct correlation between crystal structure and HER activity, thus paving the way for the design of even better electrocatalytic materials through structure–activity relationships.

Ternary Mo2NiB2 as a Superior Bifunctional Electrocatalyst for Overall Water Splitting

“…The existence of O element in the sample should be due to the unavoidable surface partial oxidation of samples, which was reported in other metal borides. [ 24 ] The B spectrum in Figure 2b is deconvoluted into two oxidation states: B 0 and B 3+ , where the B 0 is ascribed to the ternary boride and the B 3+ to boron‐oxo species on the surface.…”

“…Previous reports indicated that in metal borides, the metal and boron atoms show neutral charge state. [ 24 ] Therefore, the shift of the peak positions for Mo 3d and Ni 2p in Mo 2 NiB 2 should be ascribed to the electrons transfer from Ni atoms to the Mo atoms. The Mo atoms at low charge state are known as good catalytic sites for HER, [ 28 ] which indicates that the Mo 2 NiB 2 with electron rich Mo atoms should be a superior HER catalyst.…”

Abundant Active Sites on the Basal Plane and Edges of Layered van der Waals Fe3GeTe2 for Highly Efficient Hydrogen Evolution

“…This is an extraordinary result which showcases the ease with which the HER activity of basal plane active materials can be improved. During our recent studies of another group of basal plane active materials (transition metal diborides), we discovered that their HER activity can be drastically improved by efficiently covering the electrode, thus taking advantage of the basal plane activity. − We have applied this strategy to further improve the activity of FGT. The sonicated FGT sample was compressed into a pellet through spark plasma sintering (SPS) at room temperature to achieve a densified disk (see the Supporting Information).…”

Development Strategies in Transition Metal Borides for Electrochemical Water Splitting

“…Some studies found the series of borides in one metal and explore the mechanism and forecast the regular performance. For example, Lee et al [79] prepared purely various crystal phases of vanadium borides via the arc-melting method. The different kinds of V x B y exhibited stepped performance from VB to VB 2 (Figure 8e), requiring the overpotential of 296 mV, 204 mV at the −10 mA cm −2 in 0.5 M H 2 SO 4 , respectively.…”