Heterostructured Au@Pt/Nb2C-MXene nanocomposite as a colorimetric sensor with peroxidase-like activity for reactive oxygen species of H2O2

Bioinspired nanozymes based on two-dimensional (2D) transition metal carbide nanosheets are receiving attention because of their peroxidase-mimicking catalytic applications in bioanalysis. Herein, we report the Nb2C/Au@Pt nanocomposite-based heterostructured nanozymes for the detection of reactive oxygen species in a biological environment. The nanocomposites were fabricated by decorating 2D Nb2C-MXene with Au@Pt core–shell nanoparticles via interfacial electrostatic attraction between the transition metal carbide and noble metals. The nanocomposites were characterized using field emission scanning electron microscope, X-ray diffraction, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectroscopy, and zeta potential. The Nb2C-MXene with inherent electron and photothermal effects exhibited enhanced surface plasmon properties when adorned with Au@Pt. The Nb2C/Au@Pt nanocomposites demonstrated a synergistically enhanced peroxidase-like activity and efficiently catalyzed the 3,3′,5,5′-tetramethylbenzidine (TMB) reaction in the presence of hydroxyl radicals using H2O2. The Michaelis-Menten kinetics measurements revealed high catalytic activity of Nb2C/Au@Pt nanocomposites for TMB. Accordingly, a suitable label-free colorimetric sensing platform was established, considering an inhibitory effect on the specific detection of H2O2 in a linear range of 0.3–2.75 M. This study presents an effective strategy to design and fabricate MXene-based peroxidase-like nanozymes and demonstrates their potential in the fields of catalysis and biomedicine.