Hydrogen Evolution Reaction in Alkaline Solution: Catalytic Influence of Pt Supported on Graphite vs. Pt Inclusions in Graphite

Abstract

Graphite powders with supported Pt [5 and 20 weight percent (w/o) PtI and Pt inclusions (13 and 17 w/o) in graphite have been bonded with an inorganic polymer LaPO4 and used as cathodes for the hydrogen evolution reaction (HER) in 1 M KOH solution. Pt-supported electrodes [Pt(s)/C/LaPO4] are more active than the electrodes containing Pt inclusions in graphite [Pt(i)/C/LaPO4]. However, in high-current-density conditions (0.25 A/cm2), Pt(i)/C/LaPO4 is stable while Pt(s)/C/LaPO4 disintegrates after 24 h. The ac impedance diagrams display two semicircles on the complex-plane plot for both Pt(s)/C/LaPO4 and Pt(i)/C/LaPO4 electrodes but only one for pure graphite. The same equivalent circuit with two constant-phase elements has been used to explain the behavior of these electrodes. For both materials, the HER proceeds via the Volmer-Heyrovsk mechanism. The difference in the electroactivity of these two materials is related to the effective amount of Pt available. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.236.27.111 Downloaded on 2015-06-22 to IP

Highly efficient high temperature electrolysis

“…Other highly porous materials such as Pt/C were suggested as alternatives to the nickel electrodes. [9][10][11] Most electrode materials have been tested at temperatures up to 160 C with a slight increased thermal degradation at high temperature. [5][6][7]12,13 Conventional nickel electrodes were shown to withstand temperatures of at least 200 C, as they were used for the Apollo fuel cell system, normally operated at 204 C and successfully tested at temperatures of 260 C. 14 The separators/diaphragms serve as an ionic conducting material as well as separating the product gasses.…”

Quasi‐Amorphous Metallic Nickel Nanopowder as an Efficient and Durable Electrocatalyst for Alkaline Hydrogen Evolution

“…are based on alkaline electrolysis technology. However, in alkaline solution, the rate for hydrogen evolution reaction (HER) is at least two orders of magnitude slower than that in acidic environment, which is a great drawback for the alkaline electrolysis . Moreover, it needs to use very noble metal (platinum) HER electrocatalysts to attain low overpotential at the onset and rapid current increase with the voltage applied .…”

Hydrogen reaction at open circuit in alkaline media on Pt in a gas-diffusion electrode

“…Some HOR impedance studies in acidic and alkaline media have been performed in Pt-based GDEs [37] and Pt black microelectrodes [38]. However, eis studies have been mainly restricted to HER, which has been investigated in alkaline media at both amorphous and crystalline alloys [39][40][41], porous electrodeposits of Ni-Mo and Ni-TiO 2 [42,43], porous nickel [44] and platinum [45,46], among other materials.…”