Recent Advances in Doped Bi2O3 and its Photocatalytic Activity: A Review

Bismuth Oxide (Bi2O3) has a very promising photocatalytic ability to degrade waste pollutants under visible light irradiation because it has a small energy gap of around 2.85-2.58 eV. Although it has excellent potential as a photocatalyst, Bi2O3 has the disadvantage of a high electron-hole pair recombination rate, which will reduce its photocatalytic activity. To overcome these problems, surface modifications, defect recognition, or doping of Bi2O3 are carried out to obtain a more effective and efficient photocatalyst to degrade waste pollutants under visible light irradiation. Several studies by researchers have been described for the modification of Bi2O3 by doping. Various types of doping are given, such as doping in elements or doping in the form of compounds to form composites. Based on several studies that have been described, appropriate doping has been shown to increase the photocatalytic activity of Bi2O3. Keywords: Bi2O3, Photocatalyst, Doping

Enhancement Thermoelectric Properties of Cux-doped Nanostructure Bi-Sb-Te Thermoelectric Materials by Spark Plasma Sintering

Nanostructure Cux-doped Bi0.5Sb1.5-xTe3 thermoelectric materials was successfully prepared by Mechanical alloys and spark plasma sintering. In the reasearch, the crystallinity, particle size, and chemical composition were characterized by XRD, EDS, respectively. Thermoelectric properties with a maximum ZT value up to 1.17 has been obtained at 407 K in prepared Cu0.04-doped Bi0.5Sb1.496Te3 sample. The achieved higher ZT value is attributed that Cu as doping at the Sb sites introduced additional holes to enhance carrier mobility and Cu dopants interrupted the periodicity of lattice vibration to decrease lattice thermal conductivity. It is suggested that the as-prepared nanostructure Cux-doped Bi0.5Sb1.5-xTe3 thermoelectric materials has high potential for thermoelectric energy conversion application.

Rare earth doped metal oxide nanoparticles for photocatalysis: a perspective

Metal oxides are well-known materials that have been considered as the prominent photocatalysts. Photocatalysis is a promising way to address the environmental issues which arecaused by fossil fuel the combustion and industrial pollutants. Lots of efforts such as doping metal oxides with metals, non-metals or metals/non-metals have been made to enhance their photocatalytic activity. More specifically, in this review we have discussed detailed synthesis procedures of rare earth doped metal oxides performed in the past decades. The advantage of doping metal oxides with rare earth metals is that they readily combine with functional groups due to the 4f vacant orbitals. Moreover, doping rare earth metals causes absorbance shift to the visible region of the electromagnetic spectrum which results to show prominent photocatalysis in this region. The effect of rare earth doping on different parameters of metal oxides such as band gap and charge carrier recombination rate has been made in great details. In perspective section, we have given a brief description about how researchers can improve the photocatalytic efficiencies of different metal oxides in coming future. The strategies and outcomes outlined in this review are expected to stimulate the search for a whole new set of rare earth doped metal oxides for efficient photocatalytic applications.

Effect of Doping Element and Electrolyte’s pH on the Properties of Hydroxyapatite Coatings Obtained by Pulsed Galvanostatic Technique

Hydroxyapatite (HAp) is the most widely used calcium phosphate as a coating on metal implants due to its biocompatibility and bioactivity. The aim of this research is to evaluate the effect of the pH’s electrolyte and doping element on the morphology, roughness, chemical, and phasic composition of hydroxyapatite-based coatings obtained by pulsed galvanostatic electrochemical deposition. As doping elements, both Sr and Ag were selected due to their good osseoinductive character and antibacterial effect, respectively. The electrolytes were prepared at pH 4 and 5, in which specific concentrations of Sr, Ag, and Sr + Ag were added. In terms of morphology, all coatings consist in ribbon-like crystals, which at pH 5 appear to be a little larger. Addition of Sr did not affect the morphology of HAp, while Ag addition has led to the formation of flower-like crystals agglomeration. When both doping elements were added, the flowers like agglomerations caused by the Ag have diminished, indicating the competition between Sr and Ag. X-Ray Diffraction analysis has highlighted that Sr and/or Ag have successfully substituted the Ca in the HAp structure. Moreover, at higher pH, the crystallinity of all HAp coatings was enhanced. Thus, it can be said that the electrolyte’s pH enhances to some extent the properties of HAp-based coatings, while the addition of Sr and/or Ag does not negatively impact the obtained features of HAp, indicating that by using pulsed galvanostatic electrochemical deposition, materials with tunable features dictated by the function of the coated medical device can be designed.

Effect of Selective Lateral Chromium Doping by RF Magnetron Sputtering on the Structural, and Opto-Electrical Properties of Nickel Oxide

In this study, chromium (Cr)-doped nickel oxide (NiO) thin films were deposited by employing selective lateral doping of Cr in NiO by radio-frequency magnetron sputtering at different doping times ranging from 0 s (undoped) to 80 s. The structural, optical, and electrical properties of the resulting Cr-doped NiO thin films were investigated. Structural investigation from XRD patterns indicated that the grown Cr-doped NiO layer crystallized in a cubic phase. Broadening of the diffraction peak with increasing doping time from 0 s to 80 s led to a reduction in the crystallite size that varied from 23.52 nm to 14.65 nm. Compared with the undoped NiO, the diffraction peak along the (200) plane shifted from left to right as a function of doping time. This result indicated that Cr+3 could easily enter the NiO lattice. Results from the Hall-effect study disclosed that electrical properties of Cr-doped NiO was highly dependent on doping time. The conductivity of NiO was increased with doping time, and the highest conductivity (8.73 × 10−2 Scm−1) was achieved at a doping time of 80 s. Finally, optical investigations revealed that as doping time increased, the optical bandgap of Cr-doped NiO films dropped from 3.43 eV to 3.28 eV. The highest Urbach energy at higher doping time indicated that crystallinity became poorer, and the degree of defects increased with increasing doping time.

Antidoping Concept of Play Clean to Win Clean: Implication of Herbal Supplements uses for Athletes in Competitive Sports

The popularity of doping in competitive sports is relevant for all those involved in sports, particularly for evaluating anti-doping policy measures. However, there is a gap of information that addresses this subject so far. As a consequence, the prevalence of doping in competitive sports in resource limited countries is unknown. Even though it is challenging to uncover the exact prevalence of herbal products with prohibited activity such as doping, various methods put in place by world antidoping agency (WADA) have now been adopted to uncover parts of this particular problem, and enables the circumvention to some extend the issues of honesty, definition problems and the limits of pharmacological evidence. It is evident that current doping control test results can show a distinct underestimation of true doping prevalence in low middle income countries (LMIC). Nowadays, doping is a critical issue at international levels of sporting competitions. Athletes’ use of herbal supplements has seen a significant increase in the past two decades. At the top of the list of popular herbs used in sports are echinacea and ginseng, whereas garlic, St. John’s wort, soybean, ephedra and others are also gaining popularity or have been historically prevalent. Despite the increasing popularity of herbal supplements, recent events have illustrated possible concerns regarding efficacy and safety of herbal supplements usage. Remarkable sports performances at the end of the 20th century raised suspicions about herbal supplement use by athletes, prompting the formation of WADA. With WADA creation it was not long when the deaths of two professional athletes raised concerns that the herbal supplement ephedra, may have contributed to their deaths. These events and others have prompted clinicians and scientists to reexamine and evaluate the role of herbal supplements in competitive sports. This review attempts to give an insight into the use of herbal supplement in doping within the concept of play clean to win clean. An attempt has been made to provide guidance on the efficacy and side effect of most used herbal supplements found in sporting activities, especially in international competitive sports.

Hydrothermal Synthesis of Nitrogen, Boron Co-Doped Graphene with Enhanced Electro-Catalytic Activity for Cymoxanil Detection

A sample of nitrogen and boron co-doped graphene (NB-Gr) was obtained by the hydrothermal method using urea and boric acid as doping sources. According to XRD analysis, the NB-Gr sample was formed by five-layer graphene. In addition, the XPS analysis confirmed the nitrogen and boron co-doping of the graphene sample. After synthesis, the investigation of the electro-catalytic properties of the bare (GC) and graphene-modified electrode (NB-Gr/GC) towards cymoxanil detection (CYM) was performed. Significant differences between the two electrodes were noticed. In the first case (GC) the peak current modulus was small (1.12 × 10−5 A) and appeared in the region of negative potentials (−0.9 V). In contrast, when NB-Gr was present on top of the GC electrode it promoted the transfer of electrons, leading to a large peak current increase (1.65 × 10−5 A) and a positive shift of the peak potential (−0.75 V). The NB-Gr/GC electrode was also tested for its ability to detect cymoxanil from a commercial fungicide (CURZATE MANOX) by the standard addition method, giving a recovery of 99%.

Jamu: Javanese Doping During the Covid-19 Pandemic

Jamu is a part of traditional medicine that draws many people's attention today. This can be seen in the increasing consumption of jamu in Indonesian society. This increase can be influenced by the decision of the Indonesian people to consume jamu as an effort to prevent Covid-19. This study revealed the reasons behind the choice of jamu as an effort to prevent Covid-19 in some Indonesian people, especially in rural Javanese people where jamu is very closely related to their lives. This research was conducted in Mojorejo Village, Kebonsari District, Madiun Regency by involving 20 informants obtained through purposive sampling technique. This research was conducted from April to June 2021. The ethnographic method was used to enable the researchers to dig deeper into the informants' experiences regarding herbal medicine. The researchers analyzed the research data by coding and included secondary data to enrich the findings.Rural Javanese people choose jamu as doping during the Covid-19 pandemic for three reasons, including the tradition of drinking jamu, its immune booster properties, and the 3M (mudah, murah, manjur) [Easy, Cheap, Effective] aspects of jamu. Jamu ingredients that include ginger, curcuma, aromatic ginger, turmeric, and tamarind are believed to be able to boost their immune system during the pandemic.