Electrochemical Synthesis of a Multipurpose Pt−Ni Catalyst for Renewable Energy‐Related Electrocatalytic Reactions

Abstract

Renewable energy driven electrochemical processes are becoming increasingly important in the transition away from fossil fuels. One of the key reactions is electrochemical water splitting to generate green hydrogen which ideally could be directly integrated with a wind or solar electricity source. However, alkaline electrolysers suffer from significant degradation in performance if they are rapidly powered down under reduced sunlight conditions when directly coupled with a solar cell due to reverse current flow. In this work we address this issue by creating a truly bifunctional electrode material that is switchable between the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The synthesis method is simple whereby a Pt electrode is electrochemically activated and then immersed in a nickel nitrate solution to electrolessly deposit Ni on the surface. When this electrode is electrochemically cycled, it creates an active PtÀ Ni alloy at the Pt surface. Importantly, this electrocatalyst is switchable between both reactions without loss of activity as evidenced by an accelerated stress test over a 24 h period. An added advantage is that this PtÀ Ni electrocatalyst is also more active than Pt for the oxygen reduction reaction which opens up its applicability in fuel cells. Finally, to demonstrate the multifunctionality of this PtÀ Ni material, ethanol and ammonia oxidation is demonstrated which also shows better performance than Pt.

MOFs‐Derived N‐Doped Carbon‐Encapsulated Metal/Alloy Electrocatalysts to Tune the Electronic Structure and Reactivity of Carbon Active Sites†

“…These effects are particularly dramatic in alloys formed between first‐row transition metals and platinum‐group metals due to their great mismatch of atomic radius and electronic structure. [ 60‐61 ] Accordingly, even a small amount of precious metals could induce great changes in electronic structure and activity of active carbon sites.…”

Regulating Competitive Adsorption on Pt Nanoparticles by Introducing Pb to Expedite Hydrogen Production via Ammonia Oxidation

“…Therefore, the conclusion of the electron transfer from Pb to Pt can still be obtained from the perspective of electronegativity. This electronic interaction can result in the reduction in the empty orbital of Pt, which is able to inhibit the π electron transfers from the O atom in OH ad to the Pt atom, weakening the adsorption of OH ad to free the Pt sites. , In addition, the electron-poor Pb is conducive to adsorb OH ad for participating in the dehydrogenation process in AOR, which can also decrease the competitive adsorption of OH ad and NH 3 to enhance the AOR activity. , …”

“…35,36 In addition, the electron-poor Pb is conducive to adsorb OH ad for participating in the dehydrogenation process in AOR, which can also decrease the competitive adsorption of OH ad and NH 3 to enhance the AOR activity. 37,38 CV was applied in 0.1 M HClO 4 solution at a scan rate of 50 mV s −1 to study the basic electrochemical behavior of the samples. 39,40 The ECSAs were evaluated by calculating the integrated electric quantity of the H-adsorption area.…”

Design of Hierarchical Oxide‐Carbon Nanostructures for Trifunctional Electrocatalytic Applications

“…The stability for the full range of potential from HER to OER has been tested [ 90 ] for CPNP@NC_NCO in the potential range −0.377 to 1.722 V versus RHE and presented in Figure S25 of the Supporting Information. No significant change in OER current density was observed after 650 cycles whereas the drastic decrease in HER activity is visible.…”