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Crystal structure modification was introduced into CdWO4 via La doping strategy and the characterization results of SEM, XRD, TEM and EDS confirmed the morphology, crystal phase structure and composition of the CdWO4 and La-doped CdWO4 nanorods. Meanwhile, the partial substitution of Cd by La ions in CdWO4 nanocrystal was confirmed via some classic formulas. Excellent electrocatalytic performance was obtained on the electrochemical sensing interface when the La ions were doped into the CdWO4 lattice. The exquisite and regular rod-like 1.0% La-doped CdWO4 nanorods modified electrochemical sensor was established and applied to detect BPA with a highly sensitive detection limit (2.0 × 10−8 M). The more excellent electrocatalytic activity of 1.0% La-doped CdWO4 than other doping ratio nanomaterials was verified. The possible mechanism of the electrochemical catalysis of BPA was proposed based on the effective electrochemical analysis methods (EIS, CV and I-t) and the deductions from various physicochemical characterizations. More electron transmission channels were formed in the crystal due to the moderate amount of La ions in CdWO4 nanorods. Unprecedently, electrocatalytic performance of nanomaterials can be more efficiently promoted through regulating the doping atmosphere of crystal within the materials. This novel strategy will potentially provide a significant reference for solving the related electrocatalysis and electrochemical sensing interface's problems.

TiO2 nanosheet based flowerlike architectures with a surface area as high as 171 m2 g−1 were prepared through a solvothermal method. The sensing performance of TiO2 nanosheet based flowerlike architectures is enhanced by increasing density of surface unsaturated Ti atoms with dangling bonds through hydrogenation. We proposed a concept of the unsaturated Ti atoms serving as the sensing reaction active sites, and described in detail the sensing mechanism at the atomic and molecular level. The unsaturated Ti atoms not only generate non-contributing (free) electrons and adsorb oxygen molecules, but also catalyze the sensing reaction. In principle, the hydrogenation strategy may be used to improve sensing performances and catalytic activities of other metal oxides. The concept of the unsaturated metal Ti atoms serving as active sites can deepen understanding of the sensing and other catalytic reaction mechanisms, and provides a new insight to the design and fabrication of advanced sensing materials, catalysts and electronic devices.

The search for active semiconductor photocatalysts that can utilize adequately solar-energy remains to be an open issue. CdTe nanoflakes and nanowires with a range of texture coefficients of (111) have been synthesized. Photocatalytic activities of the CdTe nanocrystals in degradation of malachite green, methyl orange, acid red 88 and ciprofloxacin can be enhanced by increasing the texture coefficients of (111) and reducing texture coefficient of (220). The exposed polar {111} facets were found to be the active facets, and a charge separation model between polar Cd-CdTe (111) and Te-CdTe ( 1 ¯ 1 ¯ 1 ¯ ) surfaces is proposed. An internal electric field is created between polar Cd-CdTe (111) and Te-CdTe ( 1 ¯ 1 ¯ 1 ¯ ) surfaces by the spontaneous polarization, and the internal electric field drives separation of the photoinduced electrons and holes. Therefore, the CdTe nanoflakes with exposed polar {111} facets synthesized by using oleylamine as a morphology controlling agent show superior photocatalytic activity, compared with CdTe nanowires, nanocrystals with irregular shapes and commercial powders as well as CdS branched nanostructures. The charge separation model provides a clear opinion into charge transfer in the semiconductor nanocrystals with exposed active facets, and affords guidance to design more effective photocatalysts, solar cells and other photoelectronic devices.

Novel Ti/Sb2O3–SnO2/Er–PbO2 anodes were fabricated based on doping Er ions into the PbO2 crystal and enhanced electrocatalytic degradation efficiency for organic pollutants was achieved successfully. The doping principle, possible degradation pathway of methylene blue and electrocatalytic mechanism have been discussed in depth. Based on the comprehensive analysis of crystal parameters by X-ray diffraction (XRD) results and typical formulas, the doping principle was confirmed to be the partial substitution of Pb ions by Er ions in PbO2 nanocrystal and might form point defects. Additionally, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) investigation indicated that the Ti/Sb2O3–SnO2/Er–PbO2 anodes possessed higher oxygen overpotential and better conductivity than undoped electrodes. The optimum conditions for the degradation of methylene blue were obtained via studying the effects of different parameters, such as electrolyte concentration (0.01–0.4 M Na2SO4), current density (20–60 mA cm−2), initial methylene blue concentration (10–70 mg L−1) and initial pH (3–11). At the optimum conditions, the total organic carbon (TOC), the decolorization rate constant (kdec) and the energy consumption (EC) reached up to 65.34%, 0.036 min−1 and 0.08 (kWh(gTOC))−1, respectively. Moreover, the electrocatalytic degradation mechanism of the Ti/Sb2O3–SnO2/Er–PbO2 anodes to methylene blue was proposed to be that, the presence of point defects induced an increase of electron transport tunnels, and promoted the production of more hydroxyl radicals ( OH) and SO4 -. The possible electrocatalytic mineralization pathway of methylene blue at Ti/Sb2O3–SnO2/Er–PbO2 anodes was also speculated by UV–visible absorption spectroscopy, gas chromatography combined with mass spectrometry (GC-MS) and liquid chromatography combined with mass spectrometer (LC-MS). This work will provide significant references for exploring the mechanism between doped electrodes materials and electrocatalytic degradation performance.

CdSe hexagonal nanoflakes have been synthesized via a reaction of CdCl 2 -oleylamine with Se-tri-n-octylphosphine at 300 °C for 30 min. The CdSe hexagonal nanoflakes with the typical side lengths of 9.5–12.3 nm are single-crystalline wurtzite structure and are enclosed by {0 0 1} top and down surfaces. Size control of the CdSe nanoflakes from 3.3 to 18.6 nm is achieved by adjusting reaction temperature and time, and the size-dependent absorption and photoluminescence properties are observed. The formation of CdSe hexagonal nanoflakes results from the selective adsorption of oleylamine on the (0 0 1) prismatic facet. The as-obtained CdSe nanoflakes with exposed {0 0 1} facets show higher photocatalytic activity than CdSe commercial powders for degradation of malachite green. The present study motivates us to further explore new synthetic methods for the preparation of other II–VI semiconductor with a high percentage of reactive facets.