Heterojunction catalysts of ultra-thin carbon layer activated Platinum nanoparticles for bifunctional pH-universal hydrogen evolution reaction and oxygen reduction reaction.

Platinum catalysts are widely used in electrocatalytic water splitting for the hydrogen evolution reaction and in hydrogen fuel cells for the oxygen reduction. Nonetheless, the practical use of the noble metal platinum in commercial applications faces significant challenges due to its exorbitant cost and the intricate nature of its synthetic methods. In this work, nitrogen-doped carbon layers covering platinum particles (Pt@NCL) are uniformly distributed on carbon nanofiber (CNF) substrates to synthesize heterojunction catalysts (Pt@NCL-CNF). Multiple characterization methods reveal that the nanoscale ultra-thin carbon layer successfully activates platinum nanoparticles and creates a tremendous accumulation of valence electrons at the interface of the heterojunction catalysts. Furthermore, the greater the number of defects produced in the ultra-thin carbon layer of Pt@NCL-CNF during the reaction, the more active sites are exposed. Therefore, Pt@NCL- CNF exhibits much better hydrogen evolution reaction and oxygen reduction reaction performance in pH-universal electrolytes than the commercial carbon-supported platinum (Pt/C) catalyst. This study elucidates the reaction mechanism, highlighting the crucial role of the ultra-thin carbon layer within the catalyst, and also confirms the catalyst performance in device applications. The proposed method can provide a simple and feasible mass-produced approach for the preparation and application of high performance low platinum catalyst. A heterogeneous bifunctional catalyst (Pt@NCL-CNF) is engineered with a core-shell architecture, incorporating a Platinum core ensconced within an ultra-thin carbon shell, all mounted on supportive carbon nanofibers. [Display omitted] • Pt@NCL-CNF catalysts have better PH-universal HER/ORR performance than commercial Pt/C. • Illustrate the reaction mechanism for Pt@NCL-CNF heterojunction. • Reveal the interface electronic interaction and ultra-thin carbon surface formative defects. • Confirm the feasible route of ultra-thin carbon layer covering Pt-based catalysts. • Validation of the application potential of Pt@NCL-CNF in devices. [ABSTRACT FROM AUTHOR]