Efficient oxygen evolution reaction (OER) electrocatalysts are highly desired in the field of water electrolysis and rechargeable metal-air batteries. In this study, a chelate polymer, composed of copper (II) and dithiooxamide, was used to derive an efficient catalytic system for OER. Upon potential sweep in 1 M KOH, copper (II) centers of the chelate polymer were transformed to CuO and Cu(OH)₂. The carbon-dispersed CuO nanostructures formed a nanocomposite which exhibits an enhanced catalytic activity for OER in alkaline media. The nanocomposite catalyst has an overpotential of 280 mV (at 1 mA/cm²) and a Tafel slope of 81 mV/dec in 1M KOH solution. It has a seven-fold higher current than an IrO₂/C electrode, per metal loading. A catalytic cycle is proposed, in which CuO undergoes electrooxidation to Cu₂O₃ that further decomposes to CuO with the release of oxygen. This work reveals a new method to produce an active nanocomposite catalyst for OER in alkaline media using a non-noble metal chelate polymer and a porous carbon. This method can be applied to the synthesis of transition metal oxide nanoparticles used in the preparation of composite electrodes for water electrolyzers and can be used to derive cathode materials for aqueous-type metal-air batteries.

An operando bimodal atomic force microscopy system was constructed to perform nanomechanical mapping of an amorphous Si thin film electrode deposited on a Li_6.6La₃Zr_1.6Ta_0.4O₁₂ solid electrolyte sheet during electrochemical lithiation/delithiation. The evolution of Young's modulus maps of the Si electrode was successfully tracked as a function of apparent Li content x in lithium silicide (Li_xSi) simultaneously with real-time surface topography observation. At the initial stage of lithiation, the average modulus steeply decreased due to the generation of Li_xSi from intrinsic Si, followed by a moderate modulus reduction until the electrode capacity reached 3300 mAh g^-1 (Li content x = 3.46). In the following delithiation, the gradual recovery of the average modulus of Li_xSi was observed up to 1467 mAh g^-1 (Li content x = 1.54) at which delithiation stopped due to the significant volume change induced by phase transformation of Li_xSi.

Indonesia is one of the largest rubber producers worldwide. However, rubber seeds still garner less attention due to their low economic value. In fact, the rubber seeds contain 40–50% (w/w) of rubber seed oil (RSO), which is a potential candidate to be used as a feedstock in biodiesel production. In this regard, this study aims to model and simulate the production process of biodiesel from RSO via transesterification reaction, employing methanol and heterogeneous catalyst. The simulation was performed using ASPEN Hysys v11. Acid-based catalyzed esterification was implemented to eliminate soap formation, which may significantly lower biodiesel yield. The results showed that an RSO inlet rate of 1100 L/h with a methanol to oil molar ratio of 1:6 could generate around 1146 L/h biodiesel. Methanol recovery was conducted, an approximately 95% of excess methanol could be regenerated. Simulation results indicated that the properties of the biodiesel produced are compatible with modern diesel engines. Economic analysis also shows that this technology is promising, with excellent investment criteria.

Cottonseed oil (CSO) is well known as one of the commercial cooking oils. However, CSO still needs to compete with other edible oils available in the market due to its small production scale and high processing cost, which makes it a potential candidate as a feedstock for biodiesel production. To date, transesterification is the most widely applied technique in the conversion of vegetable oil to biodiesel, with glycerol produced as a by-product. Large-scale biodiesel production also implies that more glycerol will be produced, which can be further utilized to synthesize hydrogen via the steam reforming route. Therefore here, an integrated biodiesel and hydrogen production from CSO was simulated using Aspen Hysys v11. Simulation results showed that the produced biodiesel has good characteristics compared to standard biodiesel. An optimum steam-to-glycerol ratio for hydrogen production was found to be 4.5, with higher reaction temperatures up to 750 °C resulting in higher hydrogen yield and selectivity. In addition, a simple economic analysis of this study showed that the integrated process is economically viable.

Nickel oxyhydroxides (NiOOHs) are well-known for their superior activity toward oxygen evolution reaction (OER) in alkaline solutions. However, their activity toward oxygen reduction reaction (ORR) has been largely unexplored. There exist three NiOOH polymorphs: α-, β-, and γ-NiOOH, characterized by different interlayer spacing. Although still debated, γ-NiOOH with a large layer spacing has been indicated as the active phase for OER. Here, a highly crystalline γ-NiOOH was prepared in a carbon matrix by the in situ electrochemical transformation of nickel dithiooxamide Ni(dto) in 1 M KOH solution. The catalyst prepared in this way showed low overpotential not only for OER, but also for ORR in alkaline solutions. The onset potential for ORR is ~0.81 V vs. RHE, and the reaction proceeds via the 2e⁻ transfer pathway. The high OER catalytic activity and relatively low ORR overpotential make this nanocomposite catalyst a good candidate for bifunctional OER/ORR catalyst, stable in alkaline solutions.

Zero waste management program (Masaro) offers a solution to process fruit, vegetable, and food waste. They were fermented at 32oC using two types of opaque plastic bioreactors with volumes of 60 L (first 14 days of fermentation) and 120 L (next 14 days of fermentation), respectively. The product of fermentation is a special liquid fertilizer. In this study, the fertilizer is applied to promote the growth and productivity of red chilli plants (Capsicum annuum L.) for 77 days. The macro and micronutrients in the fertilizer were analyzed using atomic absorption spectroscopy. The microorganisms and the amino acids therein were also characterized. The results inform that 5 mL/L of special liquid fertilizer signifies the average height increase and leaves area enlargement of the chilli plants. The presence of rhizobacteria in the fertilizer is responsible for promoting plant growth and enhancing plant productivity. In addition, this concentration of the fertilizer provides one week earlier of flowering and fruit production, with the highest number of chilli flowers and fruits reaching 28 and 19. Conclusively, the special liquid fertilizer has shown positive impacts on crop production and quality, with lower production costs. It is also effective, sustainable, eco-friendly, and can be applied in various agricultural sectors.