Effectiveness of Nd doping and graphene oxide modification on electrochemical performance of CdSe nanorod material

Rare Earth-Based Nanomaterials for Supercapacitors: Preparation, Structure Engineering and Application

Supercapacitors (SCs) can effectively alleviate problems such as energy shortage and serious greenhouse effect. The properties of electrode materials directly affect the performance of SCs. Rare earth (RE) is known as "modern industrial vitamins", and their functional materials have been listed as key strategic materials. In the past few years, the number of scientific reports on RE-based nanomaterials for SCs has increased rapidly, confirming that adding RE elements or compounds to the host electrode materials with various nanostructured morphologies can greatly enhance their electrochemical performance. Although RE-based nanomaterials have made rapid progress in SCs, there are very few works providing a comprehensive survey of this field. In view of this, a comprehensive overview of RE-based nanomaterials for SCs is provided here, including the preparation methods, nanostructure engineering, compounds, and composites, along with their capacitance performances. The structure-activity relationships are discussed and highlighted. Meanwhile, the future challenges and perspectives are also pointed out. This Review can not only provide guidance for the further development of SCs but also arouse great interest in RE-based nanomaterials in other research fields such as electrocatalysis, photovoltaic cells, and lithium batteries.

S, N co-doped graphene quantum dots decorated CdSe for enhanced photoelectric properties

Cadmium selenide and S, N co-doped graphene quantum dots (CdSe/S, N-GQDs) nanocomposites were synthesized via a solvothermal method. The results show that S, N-GQDs have a grain size of around 5 nm and an average height of 0.5 nm, which contains only 1-2 layers of graphene sheets. The CdSe/S, N-GQDs composites exhibit distinct lattice fringes with a layer spacing of 0.24 and 0.35 nm, corresponding to (1120) and (111) crystal planes of S, N-GQDs and the cubic CdSe, respectively. The photoelectric properties of CdSe/S, N-GQDs were evaluated under ultraviolet light (365 nm) irradiation. Compared with CdSe and CdSe/GQDs, CdSe/S, N-GQDs composites have the largest photocurrent density of 4.286 × 10^-5 A cm^-2, which is about 10.5 times and 7.5 times as high as that of CdSe and CdSe/GQDs, respectively. The increase in photocurrent density of CdSe/S, N-GQDs can be attributed to the incorporation of S and N to promote separation of photogenerated carriers. Moreover, S, N-GQDs are nano-fragments of graphene, which can provide a larger specific surface area and greatly increase the contact surface with CdSe. In addition, the photoelectric properties of CdSe/S, N-GQDs composites can be adjusted by varying the doping ratio. When the doping ratio is 1:1, CdSe/S, N-GQDs have the best photoelectric performance.

Effectiveness of phase- and morphology-controlled MnO2 nanomaterials derived from flower-like δ-MnO2 as alternative cathode catalyst in microbial fuel cells

Crystal phase and morphology variations obtained by simple high-temperature annealing offer promising strategies for employing nanostructured manganese oxide as a cathode catalyst for microbial fuel cells (MFCs).