Ionic Layer Adsorption Reaction Method Research Articles

In situ formed CuInS2/SnS2 hybrid on foam-like nickel as bifunctional electrode for water splitting

Developing low-cost, efficient and robust non-noble electrocatalysts for overall water splitting is of primary importance in the future of energy solutions. In this paper, the CuInS2/SnS2 composite nanosheets array on foam-like nickel (CuInS2/SnS2/NF) was synthesized in situ via a facile hydrothermal approach and the successive ionic layer adsorption reaction method (SILAR). The as-obtained heterostructure array exhibits high electrocatalytic activity toward HER with a small overpotential of 78, 191 and 337 mV at 10, 20, and 100 mA/cm2, and remarkably enhanced OER activities with the overpotential of 258, 286 and 382 mV at 10, 20, and 100 mA/cm2 in an alkaline electrolyte. Meanwhile, the CuInS2/SnS2/NF electrode shows a lower tafel slope and outstanding electrochemical stability in both the HER and OER, displaying an excellent application foreground in the field of electrocatalytic water splitting. Moreover, the overall water splitting performance of CuInS2/SnS2/NF electrode was studied, in which the electrode serves as both the anode and cathode, and at a comparatively low voltage of 1.79 V, the current density achieves 100 mA/cm2. This study establishes a primitive strategy for obtaining mixed multimetal sulfides on self-supporting porous metal substrate, which can be used as an efficient bifunctional electrocatalyst, and is of great practical significance in future energy application.

Ag-Pi/BiVO4 heterojunction with efficient interface carrier transport for photoelectrochemical water splitting

The limitation of pristine BiVO4 photoanode severely causes the high carrier recombination efficiency and low energy conversion efficiency in the photoelectrochemical (PEC) system. In this work, the Ag-Pi/BiVO4n-n heterojunction has been rationally designed and fabricated for efficient PEC water splitting, through successive ionic layer adsorption reaction method. The built-in field of Ag-Pi/BiVO4 significantly promotes the separation efficiency of photogenerated carriers, benefiting for the participation of abundant holes in water oxidation. The photocurrent density of 40-Ag-Pi/BiVO4 has been enhanced to 2.32 mA/cm2, which is 4.5 times than that of the pristine BiVO4. Compared with the pristine BiVO4 (6.5%), the IPCE value of 40-Ag-Pi/BiVO4 achieves 22% (410 nm, 1.23VRHE). In addition, the charge injection efficiency (ηinjection) and charge separation efficiency (ηseparation) of 40-Ag-Pi/BiVO4 have been achieved to 74.36% (1.23 VRHE) and 31.57% (1.23 VRHE), respectively, revealing the excellent carriers’ transfer behavior in the both bulk and interface. The desirable stability endows Ag-Pi/BiVO4 system with a great potential in the practical application in PEC water splitting, and the corresponding mechanism for in-depth understanding the process of carriers’ transfer in Ag-Pi/BiVO4 structure has been also proposed. Therefore, the construction of Ag-Pi/BiVO4 heterojunction will provide a new insight for the configuration of efficient PEC system.

Capacitive property studies of inexpensive SILAR synthesized polyaniline thin films for supercapacitor application

The polyaniline (PANI) is an eco-friendly conductive polymer which has been considered for diverse applications. The partially oxidized phase of the PANI is useful for the charge storage application. Here, a unique nanograin/nanofiber structured PANI was grown on inexpensive stainless steel (SS) current collector by the simple oxidative polymerization process and its charge storage properties were systematically investigated. For that, the inexpensive successive ionic layer adsorption reaction method was used to grow a uniform nanostructured PANI on the SS conductor. This evolution of the nanostructure was studied with the Field emission scanning electron microscope. Furthermore, the as-prepared PANI was confirmed by the X-ray diffraction and the Fourier-transform infrared spectroscopy. In the half cell electrochemical testing, the prepared PANI exhibited a maximum specific capacitance of 710 F g−1 with a specific discharge capacity of 119 mAh−1 at 0.2 mA cm−2 in 1 M H2SO4 for the supercapacitor application. Also, by using the power-law relation it was observed that, in a charging and a discharging current, initially a contribution of the diffusive faradaic reactions is more as compared with the surface capacitive non-faradaic reactions.

Eco-Friendly NaSbS2 Quantum Dot-Sensitized Solar Cells

Ternary sulfide NaSbS2 is a low-cost, environmentfriendly semiconductor that has rarely been studied. This paper demonstrates, for the first time, solid-state NaSbS2 quantum dot-sensitized solar cells (QDSSCs). NaSbS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanoparticles were synthesized using the sequential ionic layer adsorption reaction method. Solid-state QDSSCs were fabricated from the synthesized nanoparticles using spiro-OMeTAD as the hole-transporting electrolyte. The best cell yielded an efficiency of 1.27% under 1 sun. At the reduced light intensity I0 of 10% sun, the efficiency increased significantly to 4.11% with an open-circuit voltage Voc of 0.51 V, a short-circuit current density J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</sub> of 1.68 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , and a fill factor (FF) of 47.8%. A sublinear power law of J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</sub> ∝ I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.52</sup> accounts for the large improvement in performance under low-light intensities because of the reduced carrier recombination. The external quantum efficiency (EQE) spectrum covered the spectral region of 300-750 nm with a maximum EQE value of 72% at λ = 450 nm. The present efficiency (4.11%) represents about 30% improvement over the best previous result (3.18%) of liquid-junction QDSSCs. The respectable efficiency indicates that NaSbS2 shows potential as an efficient solar absorber material.

Deposition of Tin Oxide Thin Films by Successive Ionic Layer Adsorption Reaction Method and Its Characterization.

Tin oxide thin films were uniformly deposited by successive ionic layer adsorption reaction (SILAR) method on glass substrates using ethylene diamine as a complexing agent. The proper annealing treatment in air converts as-deposited amorphous films into crystalline and removes defects, reducing strain in the crystal lattice. The films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR) spectroscopy. The film shows good optical transparency in the range of 200-1000 nm wavelength and electrical resistivity decreases upon annealing.

Study of the extrinsic properties of ZnO:Al grown by SILAR technique

Aluminum-doped ZnO thin films with pebble-like structures have been successfully deposited on glass substrates by successive ionic layer adsorption reaction method. The effect of percentage composition of the aluminum dopant on the flower-like clusters of the ZnO nanostructures on the structure, morphology, and optical properties was investigated. The ZnO thin films which were crystallized in hexagonal wurtzite structures with crystallite sizes of 44, 51, 56, and 43 nm for the intrinsic and 1, 3, and 5% Al-doped ZnO thin films, respectively. Preferred orientation of crystallites is in all cases in [001] direction perpendicular to the sample surface The Raman spectroscopy revealed decrease in the intensity of the ZnO characteristic peak due to the substitution of the Zn2+ atoms by the Al3+ and attributed to potential fluctuations of the alloy disorder. The introduction of the Al3+ dopant significantly increased the optical band gap.

Enhanced photogenerated carrier separation in CdS quantum dot sensitized ZnFe2O4/ZnIn2S4 nanosheet stereoscopic films for exceptional visible light photocatalytic H2 evolution performance.

CdS quantum dot sensitized ZnFe2O4/ZnIn2S4 nanosheet stereoscopic films were synthesized through two sequential solvothermal processes and the ionic layer adsorption-reaction method. The hydrophilic ZnIn2S4 nanosheet stereoscopic film was pre-prepared to act as a suitable host material, and then ZnFe2O4 nanoparticles and CdS quantum dots were uniformly decorated on the surface of the ZnIn2S4 nanosheet stereoscopic film to form a ternary heterostructure stereoscopic film. The band structure difference in the ternary heterostructure can promote the spatial separation and transport efficiency of photogenerated charge carriers. Meanwhile, the composite stereoscopic film has significant structural advantages and can provide a large amount of reaction active sites and outstanding visible light utilization. The superhydrophilic surface contributes to interface contact of catalyst/solution and gas detachment. These positive factors led to a significantly enhanced photocatalytic H2 evolution activity of the CdS/ZnFe2O4/ZnIn2S4 ternary heterostructure film in comparison with the pristine ZnIn2S4 and binary heterostructure film photocatalysts. The optimized CdS/ZnFe2O4/ZnIn2S4 ternary heterostructure film demonstrates the highest H2 production rate of 79.0 μmol h-1, which surpasses that of ZnIn2S4 by more than 3.2 times. This synthesis strategy can be applicable for the facile synthesis of other visible-light-driven composite film catalysts.