Weiwei Xu,Wei Tian,Linxing Meng,Fengren Cao,Liang Li
Due to its suitable band energy level and small band gap, CdIn 2 S 4 is a promising photoanode for photoelectrochemical (PEC) water splitting. Nevertheless, the serious charge recombination at the back contact and photoelectrode/electrolyte interface severely hinders its PEC activity. Herein, a facile magnetron ion-sputtering strategy is adopted to fabricate TiO 2 underlayer and NiO overlayer to modify both sides of CdIn 2 S 4 photoanode. The TiO 2 underlayer serves as an electron transport layer to promote electrons transfer from CdIn 2 S 4 to fluorine-doped tin oxide substrate and hinder holes' transportation, thus suppressing the charge recombination at the back contact. NiO, as a p-type semiconductor, forms a p-n heterojunction with CdIn 2 S 4 , inducing a built-in electric field to facilitate charge transport. Meanwhile, NiO overlayer acts as a co-catalyst to enhance surface reaction kinetics, and thereby improves the carrier injection efficiency at photoelectrode/electrolyte interface. As a result, the optimum TiO 2 /CdIn 2 S 4 /NiO photoanode exhibits photocurrent as high as 0.6 mA cm −2 at 1.23 V versus reversible hydrogen electrode, which is about 2.3 times that of bare CdIn 2 S 4 . This work provides an effective strategy to manipulate the charge carrier dynamics to improve the PEC activity of photoanode.
Yan Liu,Feng Xin,Yongsheng Xu,Zhihao Ding,Bingbing Li
Graphical We proposed a “step by step” strategy of hydrophobic treatment before dispersing Pt nanoparticles to prepare Pt/SSNs/PDMS coating. The Pt/SSNs/PDMS could not only expose more active sites, but also effectively improve the utilization of Pt. The high utilization of Pt nanoparticles improves the economy of the catalysts. Liquid-phase catalytic exchange (LPCE) of hydrogen isotopes has extensive application in upgrading of recycled water and wastewater treatment. This low-temperature catalytic exchange requires hydrophobic catalysts for keeping high exchange efficiency and catalytic stability. To eliminate diffusional influences in conventional porous catalysts, we designed a flat catalyst coating with fully exposed platinum (Pt) active sites by two steps. The hydrophobic coating was firstly established by superhydrophobic silica nanospheres (SSNs) and then Pt nanoparticles were dispersed on the surface of coating by ion sputtering. By adjusting the time of ion sputtering, the catalytic exchange efficiency of optimized catalyst coating (50-Pt/SSNs/PDMS) improved up to 86% at 60 °C and maintained stability for at least 5 h, behaving high catalytic exchange efficiency and good stability. Besides, the turnover frequency of the 50-Pt/SSNs/PDMS was 1.7 times than that of “PDMS+Pt/SSNs” prepared by “glue+power” method. The “step by step” strategy can effectively improve the utilization of Pt and provide a new idea for the preparation of Pt-based hydrophobic catalysts.
Hanyun Cheng,Xu Dong,Yang Yang,Yiqing Feng,Tao Wang,Muhammad Ali Tahir,Liwu Zhang,Hongbo Fu
Monolayer-ordered gold nanoring arrays were prepared by ion-sputtering method and used as surface enhanced Raman spectroscopy (SERS) substrates to test the individual atmospheric aerosols particle . Compared to other methods used for testing atmospheric aerosols particles, the collection and subsequent detection in our work is performed directly on the gold nanoring SERS substrate without any treatment of the analyte. The SERS performance can be tuned by changing the depth of the gold nanoring cavity as originating from coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field exhibits uniform enhancement and polarization in the ordered Au nanoring substrate, which can improve the accuracy for detecting atmospheric aerosol particles. Combined with Raman mapping, the information about chemical composition of individual atmospheric aerosols particle and distribution of specific components can be presented visually. The results show the potential of SERS in enabling improved analysis of aerosol particle chemical composition, mixing state, and other related physicochemical properties .
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