Noble Metal/MXene Nanocomposites for Electrocatalysis: Interfacial Design, Functionalization, and Structure–Activity Relationships

Abstract

MXenes provide a highly conductive and chemically tunable platform for dispersing and electronically modulating noble-metal active sites in electrocatalysis. This review critically examines noble metal/MXene nanocomposites with emphasis on how defect chemistry, surface terminations, and metal-support interactions govern catalytic activity and durability. Unlike previous reviews that primarily summarize synthesis routes, catalyst compositions, or electrochemical performance, this review establishes an interface-centered and reaction-specific framework. The literature is organized according to defect-assisted anchoring, strong and reactive metal–support interactions, surface termination, and bimetallic or intermetallic engineering. These strategies are correlated with noble-metal dispersion, coordination environment, charge redistribution, d-band modulation, intermediate adsorption, and performance in MOR, HER, ORR, and NRR. The review also discusses active-site evolution under operating conditions and identifies major limitations, including MXene oxidation and restacking, noble-metal migration and dissolution, incomplete mechanistic evidence, nonstandardized durability testing, and limited device-level validation. By integrating interfacial coordination, reaction-specific adsorption energetics, operando characterization, stability, and scalability, this review provides a distinctive framework for the rational and practical design of noble metal/MXene electrocatalysts.