Abstract
H(2)O(2) is an environmentally friendly chemical for a wide range of water treatments. The industrial production of H(2)O(2) is an anthraquinone oxidation process, which, however, consumes extensive energy and produces pollution. Here we report a green and sustainable piezocatalytic intermediate water splitting process to simultaneously obtain H(2)O(2) and H(2) using single crystal vanadium (V)-doped NaNbO(3) (V-NaNbO(3)) nanocubes as catalysts. The introduction of V improves the specific surface area and active sites of NaNbO(3). Notably, V-NaNbO(3) piezocatalysts of 10 mg exhibit 3.1-fold higher piezocatalytic efficiency than the same catalysts of 50 mg, as more piezocatalysts lead to higher probability of aggregation. The aggregation causes reducing active sites and decreased built-in electric field due to the neutralization between different nano-catalysts. Remarkably, piezocatalytic H(2)O(2) and H(2) production rates of V-NaNbO(3) (10 mol%) nanocubes (102.6 and 346.2 µmol·g(-1)·h(-1), respectively) are increased by 2.2 and 4.6 times compared to the as-prepared pristine NaNbO(3) counterparts, respectively. This improved catalytic efficiency is attributed to the promoted piezo-response and more active sites of NaNbO(3) catalysts after V doping, as uncovered by piezo-response force microscopy (PFM) and density functional theory (DFT) simulation. More importantly, our DFT results illustrate that inducing V could reduce the dynamic barrier of water dissociation over NaNbO(3), thus enhancing the yield of H(2)O(2) and H(2). This facile yet robust piezocatalytic route using minimal amounts of catalysts to obtain H(2)O(2) and H(2) may stand out as a promising candidate for environmental applications and water splitting. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material (typical Raman spectra of NaNbO(3) and V-NaNbO(3) with various doping concentrations (Fig. S1). XPS spectra of Na 1s (Fig. S2). PL spectra of solution obtained from the piezocatalytic system using NaNbO(3) and V-NaNbO(3) (10 mol%) as the catalysts after 1 h (Fig. S3). The length of NaNbO(3) and V-NaNbO(3) nanocubes calculated from XRD data of their (101) planes (Table S1)) is available in the online version of this article at 10.1007/s12274-022-4506-0.