A fundamental viewpoint on the hydrogen spillover phenomenon of electrocatalytic hydrogen evolution

Abstract

Hydrogen spillover phenomenon of metal-supported electrocatalysts can significantly impact their activity in hydrogen evolution reaction (HER). However, design of active electrocatalysts faces grand challenges due to the insufficient understandings on how to overcome this thermodynamically and kinetically adverse process. Here we theoretically profile that the interfacial charge accumulation induces by the large work function difference between metal and support (∆Φ) and sequentially strong interfacial proton adsorption construct a high energy barrier for hydrogen transfer. Theoretical simulations and control experiments rationalize that small ∆Φ induces interfacial charge dilution and relocation, thereby weakening interfacial proton adsorption and enabling efficient hydrogen spillover for HER. Experimentally, a series of Pt alloys-CoP catalysts with tailorable ∆Φ show a strong ∆Φ-dependent HER activity, in which PtIr/CoP with the smallest ∆Φ = 0.02 eV delivers the best HER performance. These findings have conclusively identified ∆Φ as the criterion in guiding the design of hydrogen spillover-based binary HER electrocatalysts.

Hydrogen spillover in complex oxide multifunctional sites improves acidic hydrogen evolution electrocatalysis

“…In addition, referring to previous study, in situ analyzing the hydrogen adsorption and desorption kinetics on catalysts can support the occurrence of hydrogen spillover 57 . To examine the hydrogen desorption kinetics, the operando CV investigations were implemented and hydrogen desorption peaks during CV scanning in the double layer region were monitored 21 , 58 .…”

“…Following a previous recognition, the second parallel component R 2 ( R 2 represents the hydrogen adsorption resistance) can reflect the hydrogen adsorption behavior on catalyst surface 24 , 57 . In view of the potential-dependent R 2 for all catalysts, it is reasonable to quantify their hydrogen adsorption kinetics via plotting log R 2 vs. overpotential and calculating the EIS-derived Tafel slopes by virtue of the Ohm’s law 57 , 59 . As displayed in Fig.…”

“…The significantly reduced slope for La 2 Sr 2 PtO 7+δ suggests its accelerated hydrogen desorption kinetics. It was reported that the hydrogen desorption kinetics for metal-support electrocatalysts could be effectively accelerated by hydrogen spillover effect 21 , 57 . Therefore, the fast kinetics of the hydrogen desorption for La 2 Sr 2 PtO 7+δ could be originated from the efficient hydrogen spillover.…”

Layered MAX phase electrocatalyst activity is driven by only a few hot spots

“…Therefore, there is an urgent need to investigate catalysts for the hydrogen production. 1–5 The layered materials such as 2D transition metal dichalcogenides (TMDs), i.e. MoS 2 and WS 2 , have been widely investigated as a promising electrocatalyst for the HER.…”

Solid-state synthesis of CdFe2O4 binary catalyst for potential application in renewable hydrogen fuel generation

“…Equally important to the nature of electrocatalysts for water splitting is the method of catalyst synthesis. Several materials such as chalcogenides 10 , nitrides 11 , sulfides 12 , carbides 13 , phosphides 14 , and oxides 15 have been explored for electrochemical water splitting process. Oxides are the most promising because of their catalytic function and ease of synthesis.…”