Engineering a local acid-like environment in alkaline medium for efficient hydrogen evolution reaction

Abstract

Tuning the local reaction environment is an important and challenging issue for determining electrochemical performances. Herein, we propose a strategy of intentionally engineering the local reaction environment to yield highly active catalysts. Taking Ptδ− nanoparticles supported on oxygen vacancy enriched MgO nanosheets as a prototypical example, we have successfully created a local acid-like environment in the alkaline medium and achieve excellent hydrogen evolution reaction performances. The local acid-like environment is evidenced by operando Raman, synchrotron radiation infrared and X-ray absorption spectroscopy that observes a key H3O+ intermediate emergence on the surface of MgO and accumulation around Ptδ− sites during electrocatalysis. Further analysis confirms that the critical factors of the forming the local acid-like environment include: the oxygen vacancy enriched MgO facilitates H2O dissociation to generate H3O+ species; the F centers of MgO transfers its unpaired electrons to Pt, leading to the formation of electron-enriched Ptδ− species; positively charged H3O+ migrates to negatively charged Ptδ− and accumulates around Ptδ− nanoparticles due to the electrostatic attraction, thus creating a local acidic environment in the alkaline medium.

Controllable synthesis of magic cube-like Ce-MOF-derived Pt/CeO2 catalysts for formaldehyde oxidation

“…The peaks centered at about 72.3 (Pt 4f 7/2 ), 75.7 (Pt 4f 5/2 ) eV, 73.0 (Pt 4f 7/2 ), and 76.3 (Pt 4f 5/2 ) eV are attributed to Pt δ + (0 ≤ δ < 2) and Pt 2+ species, respectively. 39–41 Compared with other works, the peaks of Pt species shifted to high binding energy, indicating a strong interaction between Pt species and CeO 2 by means of the formation of Pt–O–Ce and Pt-(OH) x . 36,42,43 The formation of Pt δ + should be attributed to the strong interaction between Pt and CeO 2 , which makes a small amount of Pt 0 electrons migrate to CeO 2 .…”

Tailoring Bond Microenvironments and Reaction Pathways of Single‐Atom Catalysts for Efficient Water Electrolysis

“…Oxygen-vacancy-enriched MgO facilitates H 2 O dissociation to form an H 3 O + intermediate on the MgO surface and accumulation around Pt δÀ sites during hydrogen evolution electrocatalysis. [100] Likewise, Pt atoms were supported on WO 3À x and showed an accelerated kinetic process at the interface (Figure 5b-d). In Pt SA/m-WO 3À x , the maximized interface between Pt and tungsten oxide and the shorter H-diffusion length over the Pt surface are supposed to enhance the hydrogen spillover effect.…”

“…[104] Transition metal carbides/nitrides. After the discovery that WC materials have partially Pt-like catalytic properties [100] Copyright 2022, Nature Publishing Group. b) Illustration for Pt SA/m-WO 3À x and Pt NP/m-WO 3À x .…”

“…Figure 5. a) Scheme of water dissociation. Reproduced with permission [100]. Copyright 2022, Nature Publishing Group.…”

Boosting the interfacial hydrogen migration for efficient alkaline hydrogen evolution on Pt-based nanowires

“…10,13,[19][20][21] Although hydrogen spillover was rst discovered in acidic HER systems, current research has also witnessed the spillover behavior in the alkaline HER, which is benecial to strengthening the *H supply for Pt-based binary catalysts in alkali. 10,12,22,23 It must be pointed out that because hydrogen spillover from strong to weak *H sites is intrinsically thermodynamically unfavorable, it will inevitably require an adequate driving force. 18 Moreover, the hydrogen spillover across the interfaces has to overcome the high migration kinetic barriers.…”