Graphene, the promising carbon allotrope, has recently gained substantial research attention due to its unique physiochemical properties and distinctive 2D structure. Graphene-based composites have remarkable electronic and crystal properties and have emerged as promising photocatalysts owing to their greater surface area, superior adsorption, and charge transfer capacity. In this study, we made indium-doped molybdenum trioxide (In–MoO3) nanobelts. We combined them with nanosheets of reduced graphene oxide (rGO) to create a new photocatalyst for removing organic compounds (textile colors) from industrial waste. The prepared materials' surface morphology, crystalline structure, functional group detection, light absorption capacity, and electrochemical behavior have been investigated and validated using well-established characterization techniques. We examined the photocatalytic activity of freshly produced catalysts under the same circumstances by mineralizing the MB dye. The rGO/In–MoO3 composite outperformed pure MoO3 and In–MoO3 samples in photo-mineralization activity. After being exposed to light for one hundred minutes, the rGO/In–MoO3, In–MoO3, and MoO3 photocatalysts removed approximately 96%, 64%, and 49% of the MB dye, respectively. According to the reaction kinetics, the rGO-supported In–MoO3 sample removed the dye at a rate of 0.0250/min. This rate was 2.43 and 4.03 times higher than the rate that was attained by the samples that consisted just of bare MoO3 and In–MoO3, respectively. In chronoamperometric analysis, the rGO/In–MoO3 catalyst showed a 4.68 and 1.65-fold higher transient photocurrent response than the MoO3 and In–MoO3 catalysts, respectively. The synergistic properties of the significantly conducting graphene matrix and nanoscaled In–MoO3 were primarily responsible for the rGO/In–MoO3's improved photomineralization performance. These effects increased the separation of e−-h+ and improved the light-harvesting capacity. This new research shows a practical way to make highly effective photocatalysts that can be used in wastewater treatment in industry.

Recently, two-dimensional (2D) carbon-based materials and their nanocomposites have gained considerable fascination as a photocatalysts due to their remarkable contribution towards photocatalytic water splitting and remediation. Herein, a novel 2D reduced graphene oxide (rGO) based silver doped molybdenum trioxide (Ag/MoO3) photocatalyst was synthesized successfully via hydrothermal and ultra-sonication methods. The surface structure, morphology, functional group characterization, and bandgap of the synthesized photocatalysts were analyzed using advanced physicochemical techniques. The photocatalytic performance of the prepared materials was scrutinized for Methylene blue (MB) dye degradation under solar light illumination. Because of its lower charge transfer resistance (19.54 Omega) and higher electrical conductivity (12.74 x 10(2) Sm-1) the rGO/Ag/MoO3 photocatalyst demonstrated significantly higher photocatalytic activity for dye removal than pure MoO3 and Ag/MoO3 photocatalysts. In particular, the rGO/Ag/MoO3 photocatalyst illustrated about 98% dye degradation at a rate constant (0.0571 min(-1)) greater than MoO3 (0.0097 min(-1)) and Ag/MoO3 (0.0184 min(-1)). Ag doping and the addition of rGO sheets led to enhanced optical absorbance and effectual separation of photo-induced electron-hole pairs, causing major progress in the photocatalytic behavior of MoO3. Transient photocurrent results revealed longstanding photo-excited charge carriers in the graphene-based material. (C) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Developing and fabricating highly effective semiconducting photocatalysts for wastewater treatment is a promising approach to dealing with environmental sustainability concerns. Bismuth antimony (BiSbO4) has gained considerable interest as a photocatalyst for water remediation applications. On the other hand, poor charge separation, slower charge transfer, rapid electron-hole pair recombination, and a wider bandgap severely limit its practical applications. Herein, novel rare-earth (Gd3 thorn ) doped BiSbO4 nanoparticles were fabricated via a facile hydrothermal approach, and these nanoparticles were anchored on 2D reduced graphene oxide (rGO) nanosheets to form nanocomposite (rGO/Gd-BiSbO4) to remove toxic pollutants from industrial effluents. We investigated the photocatalytic performance of fabricated rGO/Gd-BiSbO4 nanocomposites compared with Gd-BiSbO4 and pure BiSbO4 under visible light irradiation, which removes Methylene Blue (MB) organic dye. Compared with pristine BiSbO4 and Gd-BiSbO4 photocatalysts, the rGO-based Gd-BiSbO4 nanocomposite exhibited notably higher photocatalytic activity for degrading MB dye. Statistically, after 70 min of illumination under visible light, the nude BiSbO4, Gd-BiSbO4, and rGO/Gd-BiSbO4 photocatalysts degraded approximately 47.1%, 58.4%, and 95.6% of the dye in an aqueous solution, respectively. The kinetic studies showed that the rGO supported Gd-BiSbO4 photocatalyst removed the MB dye at a rate constant (k) of 0.0295 min-1, which was 2.54-fold and 3.39-fold greater than Gd-BiSbO4 (k = 0.0116 min-1), and BiSbO4 (k = 0.0087 min-1), correspondingly. The enhanced photocatalytic efficiency of the rGO/Gd-BiSbO4 nanocomposite is primarily due to its robust and unique structure, which is a result of the synergetic effects of the highly conducting rGO matrix and the Gd3 thorn ion. The rGO nanosheets promote the faster migration of photoinduced electrons and suppress electron-hole pair recombination in this nanocomposite structure. These nanosheets act as an efficient cocatalyst to provide more adsorption sites for MB molecules and accelerate the dye degradation process. The current study paves the way to developing a versatile, economical, and highly efficient rGO/Gd-BiSbO4 photocatalyst for removing organic pollutants found in industrial waste.

Fabrication of semiconductor-based photocatalysts with excellent charge separation efficiency has gained substantial attention due to their notable performance for water treatment applications. Herein, we syn-thesized a flat reduced graphene oxide-based gadolinium-doped bismuth vanadate (rGO/Gd/BiVO4) com-posite by a facile hydrothermal and ultra-sonication approach. By examining the photodegradation of Methylene Blue (MB) dye from an aqueous solution under visible light, we compared the photocatalytic behavior of the rGO/Gd/BiVO4 composite to that of pristine BiVO4 and Gd/BiVO4. The photo-excited elec-tron/hole pair recombination was suppressed by adding Gd and rGO to BiVO4. This led to rGO/Gd/BiVO4 having a faster rate (k = 0.027 min(-1)) of MB degradation than Gd/BiVO4 (k = 0.0095 min1) and pure BiVO4 (k = 0.006 min(-1)). In particular, the rGO/Gd/BiVO4 degraded almost 97% of the MB dye under visible-light irradiation in 100 min, whereas the BiVO4 and Gd/BiVO4 samples removed only 53% and 69% of the MB dye, respectively. The rGO/Gd/BiVO4 composite displayed 16-fold and 2.40-fold larger transient photocurrent responsiveness than the BiVO4 and Gd/BiVO4 samples. Subsequently, the BiVO4 and Gd/BiVO(4 )showed a charge recombination rate of 2.18 and 3.62 s, separately, which was relatively smaller than the rGO/Gd/ BiVO4 result (= 8.41 s). The increased photocatalytic activity of rGO/Gd/BiVO4 is due to the development of heterojunction between Gd/BiVO4 and the rGO sheets, which facilitates the absorption of photons as well as the separation of photogenerated electrons and holes. (C) 2022 Elsevier B.V. All rights reserved.

Magnesium ferrite (MgF), copper doped magnesium ferrite (CMgF), and their composite with rGO sheets were used to study the degradation of the organic pollutants and to perform antibacterial activity. The photocatalysts were prepared by the co-precipitation technique and characterized using X-rays diffraction (XRD), scanning electron microscopy (SEM) UV-visible, and fourier transfrom infrared microscopy (FT-IR), and photoelectrochemical analysis. The structure of the nanomaterials was confirmed via XRD. The functional group detection was carried out via FT-IR spectroscopy. The SEM technique was used to confirm the surface morphology of the prepared nanocatalysts. UV-Visible spectroscopy was used to measure the absorbance during the degradation experiment. The percentage photodegradation by CMgF@rGO of methylene blue was 92.4%, and that of benzimidazole was 50%. CMgF@rGO also showed better antibacterial activity against bacterial strains of Klebsiella pneumonia and Staphylococcus aureus. The rGO layers can enhance the photodegradation efficiency of copper doped magnesium ferrite due to an increase in surface area. The EIS study revealed that CMgF@rGO illustrated 2.59 and 1.57 times less charge transfer resistance than MgF and CMgF samples. The CMgF@rGO composite separately showed 9.7-fold and 3.9-fold greater transient photocurrent response than MgF and CMgF samples. A scavenging experiment was carried out to determine the most reactive species; and hydroxyl radicals were found to be highly active species, and electrons were the least reactive species.

Reduced graphene oxide (rGO)-based rare-earth-doped metal oxide nanocomposites have shown exceptional photocatalytic efficiency for water splitting and remediation. In this study, we used a simple wet chemical technique to create gadolinium (Gd) doped bismuth ferrite (BiFeO3) nanoparticles, which we then grafted onto an rGO using an ultrasonication strategy to create the nanocomposite (Gd-doped BiFeO3/rGO). The photocatalytic properties of the Gd-doped BiFeO3/rGO composite as produced were studied and compared to those of pure BiFeO3 and Gd-doped BiFeO3. The photocatalytic capabilities of the three synthesized materials were tested by determining their effectiveness in removing methylene blue dye (MBD) from an aqueous solution at the expanse of solar irradiation. The Gd-doped BiFeO3/rGO showed notable photocatalytic efficiency compared to bare BiFeO3 and Gd-doped BiFeO3 samples. Specifically, the Gd-doped BiFeO3/rGO photocatalyst removed 87% MB dye (rate constant similar to 0.016 min(-1)) after solar irradiation for 120 min, whereas the pure BiFeO3 and Gd-doped BiFeO3 samples degraded only 55% (rate constant similar to 0.003 min(-1)) and 66% (rate constant similar to 0.008 min(-1)) MB, respectively under the same conditions. The rGO based nanocomposite demonstrated excellent transient photocurrent response, which was 11-fold and 2.98-fold larger than pristine BiFeO3 and Gd-doped BiFeO3, respectively. The increased photocatalytic activity of rGO-based photocatalysts may be attributed to the synergistic impact of Gd doping and rGO nanosheets inclusion, which results in a redshift in light absorption. Employed strategies suppressed electron-hole re-combination and charge-transfer resistance but boosted the electronic conductivity (due to the existence of conjugated -electrons) and diffusive properties (due to nanoarchitecture). Such an effective Gd-doped BiFeO3/rGO nanocomposite may give rise to novel pathways for achieving visible light response photocatalysts.

This work describes component optimization studies for transition metal oxide composites (NiO/0.5 g SnO2 and NiO/1 g SnO2) synthesized using a simple co-precipitation process, as electrode materials for supercapacitor applications. XRD studies revealed the presence of cubic and tetragonal phases of crystals for NiO and SnO2, respectively. Crystallite sizes of NiO/0.5 g SnO2 and NiO/1 g SnO2 were determined from XRD data analysis, that were in range of ~10-11 nm. Morphological analysis revealed the formation of in homogenuous particles of NiO/0.5 g SnO2 and NiO/1 g SnO2 with great degree of aggregation. As synthesized NiO/1 g SnO2 and NiO/0.5 g SnO2 showed the specific capacitance of 1035.71 Fg(-1 )and 980.76 Fg(-1), respectively. Moreover, NiO/1 g SnO2 showed 64% capacitance retention at 5 mVs(-1) after 2000 consecutive CV cycles. In contrast, pure SnO2 exhibited specific capacitance of 648 Fg(-1) at scan rate of 5 mVs(-1), with 36% retention in capacitance. Results showed that 1 g SnO2 was the optimum concentration for NiO/SnO2 composite to get maximum electrochemical activity. High electrical conductivity and larger surface area arising from synergistic effects between NiO and SnO2 resulted in a great electrochemical response of NiO/1 g SnO2 nanocomposites. The inclusion of the SnO2 improved the electrical impedance spectroscopy results by facilitating the charge transfer.

Faster charge transport, excellent charge separation, narrow bandgap energy, lower electron-hole pair recombination rate, and high visible light absorption are the key features of an ideal photocatalyst material. Undoubtedly, semiconductor-based photocatalysts having remarkable charge separation efficiency have attracted considerable attention for degrading hazardous organic pollutants from contaminated water. So herein, a novel composite of reduced graphene oxide (rGO) supported by gadolinium doped bismuth yttrium oxide (Gd-BiYO3/rGO) was prepared by simple precipitation and ultrasonication method. The photocatalytic efficiency of the GdBiYO3/rGO composite was examined comparatively with pure BiYO3 and Gd-BiYO3 samples to degrade Methylene Blue (MB) dye under visible light irradiation. The Gd doping and rGO incorporation into BiYO3 increased the conductivity, improved the charge transfer efficiency, and impeded the charge recombination, resulting in superior photocatalytic activity of Gd-BiYO3/rGO. The kinetic studies exhibited the 96.2%, 61.5%, and 48.3% degradation of MB after 80 min irradiation of 1 SUN visible light under Gd-BiYO3/rGO, Gd-BiYO3, and BiYO3, respectively. The Gd-BiYO3/rGO composite degraded the MB dye at a rate (k = 0.0328 min(-1)) that is 5.05 and 2.68-fold higher than pure BiYO3 and Gd-BiYO3, correspondingly. The transient photocurrent response of GdBiYO3/rGO was comparatively 4.7 and 2.8 times greater than that of BiYO3 and Gd-BiYO3 photocatalysts, respectively. The dominant photocatalytic performance of Gd-BiYO3/rGO is primarily ascribed to the formation of heterojunctions between rGO nanosheets and Gd-BiYO3, which facilitate higher visible light absorbance, effective charge separation, and transfer through interfacial layers, more dye adsorption, lower charge transfer resistance, and hamper electron-hole pair recombination. Overall, the electrochemical results suggest that the current study provides an effective way to synthesize a heterostructure photocatalyst for removing organic pollutants from industrial effluents.

Herein, an easy co-precipitation method was adopted to fabricate Al-doped ZnO nanoflakes as a photocatalyst to remove noxious organic dye from industrial waste. The silica (SiO2) additive, owing to its network structure and excessive hydroxyl groups (Si-OH), has a great potential to capture dye molecules in its porous network. Application studies have shown that the Al-doped ZnO/SiO2 nanohybrid is more suitable for practical application because it eliminates almost 95 % of methylene blue (MB) dye after 120 minutes of exposure to solar light irradiation. The exceptional photodegradation efficiency of the Al-doped ZnO/SiO2 nanohybrid can be accredited to its narrower optical band gap, distinctive texture, hybrid composition, and good dye holding ability. The Al-doped ZnO nanoflakes exhibited a superior photocurrent response that was 4.60 times more than the bare ZnO response. Furthermore, EIS and Mott-Schottky studies reveal that the Al-doped ZnO catalyst facilitates the effective charge separation/transfer process and impedes electron-hole pair recombination, resulting in enhanced photocatalytic activity .

Elevated specific capacitance (Csp), higher surface area, faster charge transport, exceptional chemical stability, lower diffusion resistance, and a porous structure are the key features of the ideal electrode material. Undoubtedly, transition metal oxides (TMOs) have a better Csp, but their limited surface, bulky structure, and lower conductivity are the main obstacles to limiting their applications as an electrode material. So we adopted several strategies to fabricate the MoO3 electrode, an ideal electrode because of its integrated electrochemical characteristics. Firstly, the MoO3 sample was manufactured at the nanoscale to tune the specific surface area, reduce the bulk contribution, and minimize the diffusion resistance. Secondly, a doping strategy has been used to get an Agdoped MoO3 sample with enhanced intrinsic conductivity. The carbonaceous nanomaterials, especially reduced graphene oxide (rGO), due to their exceptional electrical conductivity, good chemical stability, higher surface area, and distinctive structure, have an excessive aptitude to boost the electrochemical aptitude of transition metal oxides. Therefore, thirdly, we used a composite formation strategy to fabricate a rGO/Ag/MoO3 nanocomposite with improved extrinsic conductivity and faster charge transfer characteristics. Finally, we decorated the rGO/Ag/MoO3 sample on the current collector via the Nafion binder because of its superior charge transfer characteristics. The nanocomposite-based electrode exhibited excellent Csp (422.16 F/g @ 1 Ag), exceptional rate performance (>33% at 7 fold higher current density) and superior cyclic stability (88.21% after 5000 cycles). These remarkable and integrated electrochemical characteristics of the nanocomposite are the outcome of the synergistic belongings of all adopted strategies. The electrical and electrochemical results suggest that using several strategies to make the perfect electrode is a productive approach.

In this article, we have highlighted limitations of existing structures of control chart for unknown parameters by considering various circumstances of a process. The circumstances include availability of limited samples for estimating control limits, probability distribution is unknown and collected data are highly skewed. To tackle with the limitations, we have proposed generalized skewness correction structure of chart. For proposing the required structure, we have developed skewness correction based dispersion estimators and corrected control limits multipliers to replace with known probability distribution based dispersion estimator and control limits multipliers. The proposed generalized skewness structure is dependent on the amount of skewness of gathered data from an ongoing process instead of restricted assumptions. Results illustrate that actual false alarm rate of proposed structure remains close to true false alarm rate as compared to existing structures when assumptions are violated. Besides, a real-life example from petrochemical process is presented for explaining the implementation procedure of proposed structure.

In this work, nanocomposites of carbon allotropes with TiO2 have been used as photoanodes to improve the photovoltaic performance of dye-sensitized solar cells (DSSCs). Multi-walled carbon nanotubes and graphene materials have been mixed with TiO2 paste to form nanocomposites. Transmission Electron Microscopy (TEM) has been used to confirm the dispersion of MWCNTs and graphene materials in TiO2. The electrochemical impedance spectroscopic, current-voltage characteristics and incident photon-to-current efficiency have been carried to characterize DSSCs. Results demonstrate that nanocomposite photoanodes enhance the power-conversion-efficiency of DSSCs. However, results also show that graphene/TiO2 based DSSC exhibits PCE of 5.25%, which is about 14% higher than MWCNTs/TiO2 based solar cell (4.20%). (C) 2018 Elsevier B.V. All rights reserved.

Accumulation of environmental dust and consequent mud formation on optically active surfaces block the incident solar radiation, and thus reduce the efficiency of photovoltaic cells. Silicon is widely used in photovoltaic devices. The aim of this work is to examine the consequences of accumulation of dust and adhesion of mud on the textural, chemical, and optical properties of silicon wafers. Morphological characteristics and elemental investigation of dust sample were performed by using SEM-energy dispersive X-Ray spectroscopy (EDS). Dynamic light scattering method was utilized to determine the particle size distribution. The presence of major and minor constituent minerals was confirmed by using fourier transform infrared spectroscopy (FTIR). Similarly, SEM-EDS, UV-visible spectroscopy, and X-ray diffraction were employed to investigate the dried mud films. Microtribometer has been employed to find the work done against the adhesion of dry mud. The results specify that ionic compounds in the dust greatly affect the optical, mechanical, and morphological properties of silicon wafers. Moreover, they also enhance the work done against the dry mud removal upon drying.