Surface functionalization of wafer-scale two-dimensional WO3 nanofilms by NM electrodeposition (NM = Ag, Pt, Pd) for electrochemical H2O2 reduction improvement

Surface functionalization of two-dimensional (2D) WO3 nanofilms by noble metal (NM) nanoparticles (NM = Ag, Pt and Pd) was successfully achieved for the first time via combination of the atomic layer deposition (ALD) process and electrochemical deposition method. Deposited NM nanoparticles were uniformly in the particle size and homogeneously dispersed on the surface of 2D WO3. They represented electrochemically active metal-semiconductor hybrid nanocomposites with the larger electroactive area, and consequently, substantially enhanced the electrochemical H2O2 detection of the device based on functionalized 2D WO3 nanofilms. Functionalization by Ag was found to be more efficient compared to the same functionalization by Pt and Pd nanoparticles. Particularly, Ag200-WO3 nanofilms exhibited the best electrochemical performance with a high sensitivity of 282 μA mM cm−2, extremely wide linear H2O2 concentrations range from 0.2 μM to 33.6 mM, a low detection limit of 0.1 μM, fast response time of 2 s and an excellent selectivity and long-term stability. Surface functionalization by NM nanoparticles approach has clearly demonstrated the great potential in the development of hybrid nanostructured electrode for various devices with enhanced electrochemical capabilities.