# Harnessing Controlled Dealloying–Support Coupling for Ultrastable PtNi Catalysts in PEMFC Applications

## TL;DR

A new method creates stable PtNi catalysts for fuel cells by combining alloying and dealloying processes, leading to high performance and durability.

## Contribution

A controllable alloying–dealloying strategy is introduced to create ultrastable PtNi catalysts with enhanced durability and performance.

## Key findings

- Pt1Ni1-x@Nix_NC catalysts show a half-wave potential of 0.932 V and a mass activity of 2.028 A mgPt−1.
- The catalyst retains 91.9% of its initial performance after extensive cycling in PEMFCs.
- The strategy suppresses agglomeration and strengthens metal–support interactions via Ni–N/C moieties.

## Abstract

Platinum–transition metal (PtM) alloys are among the most promising oxygen reduction reaction (ORR) catalysts, yet their practical deployment in proton‐exchange membrane fuel cells (PEMFCs) is hindered by transition‐metal dissolution, particle coarsening, and insufficient durability. Moreover, conventional alloying or intermetallic ordering strategies often aggravate these issues by inducing severe nanoparticle aggregation and instability. Here we report a controllable alloying–dealloying strategy to construct PtNi nanoparticles confined in an N‐doped carbon framework (Pt1Ni1‐x@Nix_NC). Ammonia‐assisted dealloying produces a Pt‐rich shell with an alloyed core, while the N‐doped carbon anchors the released Ni atoms form Ni–N/C moieties, thereby suppressing agglomeration and strengthening metal–support interactions. This coordination–support coupling optimizes Pt 5d orbital occupation, weakens oxygen adsorption, and accelerates ORR kinetics. Consequently, Pt1Ni1‐x@Nix_NC exhibits a half‐wave potential of 0.932 V and an ultrahigh mass activity of 2.028 A mgPt−1, which is 8.75‐fold higher than commercial Pt/C and among the best values reported to date for PtNi‐based catalysts. Remarkably, it shows only a 6 mV half‐wave potential loss after 30,000 cycles, demonstrating exceptional durability. In PEMFCs, the fuel cell delivers 975 mW cm−2 peak power density and retains 91.9% of initial performance, underscoring a generalizable approach for designing durable, high‐performance low‐PGM catalysts for next generation PEMFCs.

A controllable alloying–dealloying strategy constructs PtNi core–shell nanoparticles confined within an N‐doped carbon framework. Selective ammonia‐assisted dealloying forms a Pt‐rich shell while immobilizing Ni as Ni–N/C moieties, synergistically stabilizing the catalyst. The resulting structure delivers exceptional ORR activity and durable, high‐power performance in practical PEM fuel cells.