Bi2S3 nanotubes and nanoparticle in the form of thin films were deposited on fluorine doped SnO2 (FTO) coated conducting glass substrates by Aerosol Assisted Chemical Vapor Deposition (AACVD) using tris-(N,N-diethyldithiocarbamato)bismuth(III), [Bi(S2CN(C2H5)2)3]2 (1) as a precursor. Thin films were deposited from solutions of (1) in either chloroform, dichloromethane, or a 1:1 mixture of chloroform and toluene at temperature between 350 to 450 °C and characterized by X-ray diffraction (XRD), UV−vis spectroscopy, field emission gun scanning electron microscopy (FEGSEM), and energy dispersive X-ray (EDX) analysis. FEGSEM images of films deposited from chloroform or dichloromethane exhibit well-defined and evenly distributed nanotubes with an average internal diameter of 40 nm. Films deposited from chloroform/toluene, on the other hand, have compact nanostuctured morphology. Bandgaps of 1.85 and 1.8 eV were estimated for nanotubes and nanoparticles, respectively, by extrapolating the linear part of the Tauc plot recorded for the films. The n-type Bi2S3 thin films display a reasonable photoactivity under illumination and are thus promising candidates for photoelectrochemical applications. The photoelectrochemical characteristics recorded under AM 1.5 illumination indicated photocurrent density of 1.9 mA/cm2 and 1.0 mA/cm2 at 0.23 V versus Ag/AgCl/3 M KCl for the films deposited from chloroform and chloroform/toluene, respectively. The photocurrent is among the highest reported for any Bi2S3 photoelectrode to date. Repeated illumination cycles show that the Bi2S3 thin films display a reasonable photosensitivity and response indicating their potential to be used in photodetector and optoelectronic nanodevice applications.

An effcient electrocatalytic Pd system, prepared via the AACVD method, is presented executing high activity water oxidation at 1.43 V vs RHE; η = 200 mV while exceeding the benchmark performance of IrO2.

Pristine Mn2O3 and Ag-Mn2O3 composite thin films have been developed on fluorine doped tin oxide (FTO) coated glass substrates at 450 °C by aerosol assisted chemical vapor deposition (AACVD) using a methanol solution of a 1 : 2 mixture of acetatoargentate(i), Ag(CH3COO), and a newly synthesized manganese complex, [Mn(dmae)2(TFA)4] (1) (dmae = N,N-dimethylaminoethanolate, TFA = trifluoroacetate). The phase purity and stoichiometric composition of the films were investigated by X-ray diffraction (XRD) and Raman spectroscopy techniques. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses revealed a Ag to Mn ratio of 1 : 2 and further confirmed the uniform dispersion of Ag nanoparticles into the Mn2O3 structure. Optical studies showed a direct band gap of 2.0 eV for the pristine Mn2O3 film that was lowered to 1.8 eV for Ag-Mn2O3 due to the plasmonic interaction of Ag with Mn2O3. The Ag-Mn2O3 composite film displayed enhanced photocatalytic activity in photoelectrochemical (PEC) water splitting and yielded a photocurrent of 3 mA cm(-2) at 0.7 V versus Ag/AgCl which was 1.6 times higher than a pristine Mn2O3 film alone, under AM 1.5 G illumination (100 mW cm(-2)). The high PEC efficiency is mainly due to the plasmonic effect of Ag nanoparticles, which enhances the visible light absorption, efficient electron-hole separation and high carrier mobility of the Ag-Mn2O3 photoelectrode. The charge carrier density of Ag-Mn2O3 is two times higher than the pristine Mn2O3 as calculated by the Mott-Schottky plot. Based on the PEC studies a mechanism is proposed to elucidate the high activity of Ag-Mn2O3 in PEC water splitting.

Water oxidation catalysis is gaining more attention in recent times owing to its potential for solar and chemical energy conversion and for green fuel generation. The overwhelming hurdle in this quest is to develop a noble-metal-free, efficient, low overpotential water oxidation electrocatalyst exhibiting tremendous stability and to be obtained from earth-abundant materials. We show here unique copper-based water oxidation electrocatalyst derived from thin film Cu-colloidal nanoparticles and is highly efficient, robust for water oxidation. The catalyst advantageously exhibits nanobeads and nanorods type mixed morphological features with narrow size distribution. The onset for oxygen evolution reaction occurs at a small potential of 1.45 V RHE (η = 220 mV) which is the lowest observed relative to other copper-based materials. The catalyst also maintains remarkable stability during long-term water electrolysis experiments. Moreover, the catalyst shown to exhibit a high electroactive area with a Tafel slope of 52 mV dec 1À , high TOF of 0.81 s 1À and mass activity of 87 mA mg À 1 . Copper is an interesting material because it can also serve as CO 2 reduction catalysts at the cathode side. The straightforwardly prepared, handy, and inexpensive Cu-based electrocatalytic system is a flexible catalyst for electrooxidation of water and for chemical energy conversion and is an attractive alternative to Pt, Ir, and Ru based electrocatalysts obtained from expensive resources and tedious methods.

An improved and facile aerosol-assisted chemical vapor deposition (AACVD) process for the production of palladium thin film on indium tin oxide (PdNP-ITO) electrodes was described and applied for the electrochemical detection of hydrogen peroxide (H 2 O 2 ). The detailed characterization of the films by X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis proved the high crystallinity and phase purity of the nanosized metallic palladium films without the evolution of any elemental impurities from the precursor compound. The as-prepared electrodes were used for nonenzymatic amperometric H 2 O 2 detection via electrochemical reduction. The LOD was 40.8 nM with a high sensitivity of 760.84 μA/(μM cm 2 ). From the experimental scan rate variation analysis, the reduction of H 2 O 2 on the PdNP-ITO electrode surface was determined to be adsorption controlled. For this process of adsorption, we calculated the number of electrons involved during adsorption (n), the charge transfer coefficient (α), and, finally, the rate constant (k s ). The process of adsorption of H 2 O 2 on each of the characteristic metallic planes was further studied via Monte Carlo simulations (MCSs). We accounted for both molecular O 2 and H 2 O during the simulations to understand the effects of oxygen and solvent on adsorption since all experiments were conducted in an air-saturated solution. Several numbers of the adsorbate−metal substrate configurations were obtained for the simulations on each crystalline Pd plane, confirming the firm adsorption of H 2 O 2 in the presence of O 2 and H 2 O. Based on analysis of the results from the electroanalytical procedures and MCSs, possible reduction reaction mechanism pathways were proposed.

Severe acute respiratory syndrome (SARS-CoV-2), the causative agent of the global pandemic, which has resulted in more than one million deaths with tens of millions reported cases, requires a fast, accurate, and portable testing mechanism operable in the field environment. Electrochemical sensors, based on paper substrates with portable electrochemical devices, can prove an excellent alternative in mitigating the economic and public health effects of the disease. Herein, we present an impedance biosensor for the detection of the SARS-CoV-2 spike protein utilizing the IgG anti-SARS-CoV-2 spike antibody. This label-free platform utilizing screen-printed electrodes works on the principle of redox reaction impedance of a probe and can detect antigen spikes directly in nasopharyngeal fluid as well as virus samples collected in the universal transport medium (UTM). High conductivity graphene/carbon ink is used for this purpose so as to have a small background impedance that leads to a wider dynamic range of detection. Antibody immobilization onto the electrode surface was conducted through a chemical entity or a biological entity to see their effect; where a biological immobilization can enhance the antibody loading and thereby the sensitivity. In both cases, we were able to have a very low limit of quantification (i.e., 0.25 fg/mL), however, the linear range was 3 orders of magnitude wider for the biological entity-based immobilization. The specificity of the sensor was also tested against high concentrations of H1N1 flu antigens with no appreciable response. The most optimized sensors are used to identify negative and positive COVID-19 samples with great accuracy and precision.

Greenockite (CdS) nanostructured thin films are deposited on soda and FTO conducting glass substrates by aerosol‐assisted (AA)CVD using a single‐source precursor bis‐(N,N‐dicylcohexyldithiocarbamato)(pyridine)cadmium(II), Cd[S2CNCy2]2.py (1), in pyridine, toluene, and THF solutions in the temperature range 350–450 °C. The precursor 1, characterized by physicochemical methods, undergoes facile thermal decomposition at 350 °C to give a stable residual mass of CdS. The thin films deposited from pyridine solution, and characterized by X‐ray diffraction (XRD), UV‐vis spectroscopy, field‐emission scanning electron microscopy (FESEM), and energy dispersive X‐ray (EDX) techniques, exhibit a band gap of 2.4 eV and a photocurrent density of 1.3 mA cm−2 at 0.4 V versus Ag/AgCl/3M KCl, suggesting their suitability for application in photoelectrochemical (PEC) cells.

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