Development of Photothermal Catalyst from Biomass Ash (Bagasse) for Hydrogen Production via Dry Reforming of Methane (DRM): An Experimental Study.

Conventional hydrogen production, as an alternative energy resource, has relied on fossil fuels to produce hydrogen, releasing CO2 into the atmosphere. Hydrogen production via the dry forming of methane (DRM) process is a lucrative solution to utilize greenhouse gases, such as carbon dioxide and methane, by using them as raw materials in the DRM process. However, there are a few DRM processing issues, with one being the need to operate at a high temperature to gain high conversion of hydrogen, which is energy intensive. In this study, bagasse ash, which contains a high percentage of silicon dioxide, was designed and modified for catalytic support. Modification of silicon dioxide from bagasse ash was utilized as a waste material, and the performance of bagasse ash-derived catalysts interacting with light irradiation and reducing the amount of energy used in the DRM process was explored. The results showed that the performance of 3%Ni/SiO2 bagasse ash WI was higher than that of 3%Ni/SiO2 commercial SiO2 in terms of the hydrogen product yield, with hydrogen generation initiated in the reaction at 300 °C. Using the same synthesis method, the current results suggested that bagasse ash-derived catalysts had better performance than commercial SiO2-derived catalysts when exposed to an Hg-Xe lamp. This indicated that silicon dioxide from bagasse ash as a catalyst support could help improve the hydrogen yield while lowering the temperature in the DRM reaction, resulting in less energy consumption in hydrogen production.

Correlating the effect of preparation methods on the structural and magnetic properties, and reducibility of CuFe2O4 catalysts.

CuFe2O4 spinel oxide has attracted research interest because of its versatile practical applications, especially for catalysis. In this study, nanometre-sized CuFe2O4 particles were prepared by three different methods, including nanospace confinement in SBA-15, hard template removal, and sol-gel combustion. The relationship between structure, size, magnetic behaviour, and reducibility of the catalysts was further investigated by various advanced techniques. Samples prepared by impregnation and hard template removal show high surface area and small crystallite size with superparamagnetic behaviour. In contrast, the sol-gel sample exhibits ferromagnetic properties with a large crystallite size and low surface area. Although all samples present a tetragonal crystal structure, the distributions of Fe and Cu cations in tetrahedral and octahedral sites in the spinel structure are different. The reducibility results demonstrate that the supported CuFe2O4/SBA-15 shows the lowest reduction profile. These results could suggest that the synthesis method strongly affects the crystal properties and cation distribution in the spinel structure, microstructure, surface area and reducibility, which are among the most relevant physicochemical properties for the catalytic activity.

Poisoning-Resistant NOx Reduction in the Presence of Alkaline and Heavy Metals over H-SAPO-34-Supported Ce-Promoted Cu-Based Catalysts.

Selective catalytic reduction (SCR) of NOx using NH3 in the presence of alkaline and heavy metals is still an issue in the application of a stationary source. Reported here is the rational design of a novel H-SAPO-34-supported ceria-promoted copper-based catalyst (CuCe/H-SAPO-34) that demonstrates exceptional resistance against alkali (K), alkaline earth (Ca), and heavy metal (Pb) poisoning during SCR of NOx. The H-SAPO-34 support contained numerous acid sites that allowed Cu-based catalysts to maintain their catalytic activity while also resisting poisoning by K and Ca. Decorating the catalyst with CeO2 promoted the low-temperature deNOx activity by accelerating the redox cycle with Cu species and assisted the H-SAPO-34 in capturing Ca and Pb. H-SAPO-34-supported ceria-promoted copper oxide catalysts prevented the irreversible combination of K, Ca, or Pb with the active centers, providing the catalyst with excellent poisoning resistance. This work provides a strategy for the development of high-performance, poisoning-resistant catalysts for NH3-SCR of NOx in the presence of alkaline and heavy metals.

Dual Promotional Effects of TiO2-Decorated Acid-Treated MnO x Octahedral Molecular Sieve Catalysts for Alkali-Resistant Reduction of NO x.

Alkali metals generated during waste incineration in power stations are not conducive to the control of nitrogen oxide (NO x) emission. Hence, improved selective catalytic reduction of NO x with ammonia (NH3-SCR) in the presence of alkali metals is a major issue for practical NO x removal. In this work, we developed a novel TiO2-decorated acid-treated MnO x octahedral molecular sieve (OMS-5(H)@TiO2) catalyst with improved alkali-resistant NO x reduction at low temperature, and the dual promotional effects of OMS-5(H)@TiO2 catalysts were clarified. It was found that the special structure of the acid-treated MnO x octahedral molecular sieve (OMS-5(H)) was responsible for the trapping of alkali metals and high deNO x activity at low temperature. Subsequently, the decoration by TiO2 further improved the redox properties by accelerating the high ratio of Mn4+ and Oα on the surface of the highly active (OMS-5(H)@TiO2) catalyst. Moreover, a thorough mechanism study via in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTs) demonstrated that the acid treatment led to remarkable increment of acid sites, which enabled the catalyst to resist alkali metals in the form of ion exchange. Meanwhile, the decoration of TiO2 further increased the strength of the Lewis acid sites, assisting more active intermediate species to effectively take part in the deNO x reaction. Besides, a "fast SCR" process was observed to certify that the decoration of TiO2 promoted the improvement of low-temperature activity in the presence of alkali metals. The dual effects combining OMS-5(H) with TiO2 decoration in terms of alkali metal resistance and high catalytic activity at low temperature proved that the high-performance deNO x catalyst was successfully developed in this work. The work paves a way for the development of superior low-temperature SCR catalysts with improved NO x reduction efficiency in the presence of alkali metals.

Preparation and electrochemical performance of nitrogen-enriched activated carbon derived from silkworm pupae waste.

In this study, nitrogen-enriched activated carbon from silkworm pupae waste (P-AC) was successfully prepared and its electrochemical performances in aqueous and organic electrolytes were investigated. Silkworm pupae waste is beneficial because it is a nitrogen-enriched, inexpensive, and locally available material. The preparation process includes hydrothermal treatment of the silkworm pupae waste at 200 °C, and chemical activation using zinc chloride at activation temperatures of 700, 800 and 900 °C (P700, P800, and P900, respectively). The nitrogen content in the P-ACs was approximately 3.8-6.4 at%, decreasing with activation temperature, while the surface area was approximately 1062-1267 m2 g-1, increasing with activation temperature. Compared to a commercial AC, the P-ACs show higher nitrogen content but lower surface area. Furthermore, the P800 exhibited superior specific capacitance (154.6 and 91.6 F g-1 in aqueous and organic electrolytes) compared to a commercial AC despite possessing smaller surface area. The high nitrogen content enhanced the pseudocapacitance and improved the electrical conductivity of the P-ACs. These properties were confirmed by relatively low series and charge transfer resistances, a capacity retention higher than 88% at a current density of 0.5 A g-1 and excellent cycling stability demonstrated by maintaining 97.6% of its capacitance after 3000 cycles. These results demonstrate that silkworm pupae waste is a viable source of nitrogen-enriched AC for application in supercapacitors.

Development of tailor-made synergistic cellulolytic enzyme system for saccharification of steam exploded sugarcane bagasse.

Designing a tailor-made synergistic system is a promising strategy for developing an effective enzyme for saccharification of lignocellulosic materials. In this study, a cellulolytic enzyme mixture comprising selected core recombinant enzymes for hydrolysis of sugarcane bagasse pretreated by alkaline-catalyzed steam explosion was optimized using a mixture design approach. The optimized enzyme system comprised a cellobiohydrolase (Cel7A) from Talaromyces cellulolyticus, an endo-glucanase (Cel7B) from Thielavia terrestris, a ß-glucosidase (BGL) and an endo-ß1,4-xylanase (XYN) from Aspergillus aculeatus at the ratio of 0.34:0.27:0.14:0.25. The maximum reducing sugar yield of 797 mg/g biomass, comprising 543 and 96.8 mg/g glucose and xylose, respectively were achieved, equivalent to 92.44% and 47.50% recoveries, respectively from the pretreated substrate at the enzyme dosage of 20 mg/g biomass. The sugar yield from the quaternary enzyme mixture was 17.37% higher than that obtained with Accellerase 1500.