The present study reports the use of one-dimensional carbon wrapped VO2(M) nanofiber (VO2(M)/C) as a cost-effective counter electrode for dye-sensitized solar cells (DSSCs); where M denotes monoclinic crystal system. Uniform short length nanofiber was synthesised by a sol-gel based simple and versatile electrospinning and post carbonization technique. The investigation of nanostructure and morphological analysis were performed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscope (TEM) with EDAX. The electrochemical response was comprehensively characterized by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization. The electrochemical analysis of the VO2(M)/C nanofiber counter electrode exhibits significant electrocatalytic activity towards the reduction of triiodide and low charge transfer resistance at the electrode-electrolyte interface. The DSSCs fabricated with carbon-wrapped VO2(M) nanofiber CE showed high power conversion efficiency of 6.53% under standard test condition of simulated 1SUN illumination at AM1.5 G, which was comparable to the 7.39% observed for conventional thermally decomposed Pt CE based DSSC under same test conditions. This result encourages the next step of modification and use of low-cost VO2(M) as an alternate counter electrode for DSSCs to achieve a substantial efficiency for future energy demand.

Hydrogen production using novel catalysts is regarded as one of the most needed technology for the future economic needs and water splitting to give H2 gas, which is a challenging task for large-scale production. This work reports the synthesis of Meso-Cu-BTC metal organic framework and further used for understanding its role in electrochemical hydrogen evolution reaction (HER) in 1 M NaOH solution. Meso-Cu-BTC electrocatalyst showed a less overpotential of 89.32 mV and an onset potential of 25 mV with an appreciable current density. Results show a low Tafel slope of 33.41 mVdec−1 and long-term durability. Thus, the overall results show that Meso-Cu-BTC acted as a good candidate for electrocatalysis towards hydrogen evolution.

A vanadium nitride xerogel (VNXG) was synthesised by a simple and effective method of ammonialising a vanadium pentoxide xerogel at a higher temperature. The electrochemical and photo-current studies were performed towards a counter electrode for DSSC.

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The nanostructure of titanium nitride was synthesized and investigated as a counter electrode (CE) to replace the conventional platinum CE for dye-sensitized solar cells (DSSCs). Titanium nitride nanoflower buds (TiN NFBs) were successfully prepared by a simple and efficient method of ammonialization of hydrothermally prepared titanium dioxide nanobuds with mixed anatase and rutile phase. Titanium nitride, with its unique nanostructure, exhibits good surface property with a wide range of porosity distribution, which is attributed to the possible electrocatalytic active sites. The electrochemical studies performed show that TiN NFBs demonstrate high electrocatalytic activity toward the iodide/triiodide electrolyte and exhibit good charge transfer kinetics with low charge transfer resistance comparable to the performance of the platinum electrode. The photocurrent voltage characteristics of the TiN NFB CE assembled DSSC shows that it achieves a power conversion efficiency (PCE) of 7.0%, which is very close to the PCE reached for the Pt CE based DSSC (7.4%). The 30 day stability study reveals the highly stable performance of the TiN NFB CE based DSSC and good corrosion resistance toward the iodide/triiodide redox electrolyte. Thus, the overall performance of the TiN NFB encourages further research to prepare different TiN nanostructures to replace the conventional costly Pt CE for large area DSSCs to reach the consumer market.