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Abstract High cost and low efficiency of cathode catalyst as well as the sluggish oxygen reduction reaction (ORR) remain the main obstacles to the practical application of direct glucose alkaline fuel cells (DGAFCs). Herein, sponge-like porous carbons fortified with transition metal, nitrogen, and phosphorus (denoted by M-N/P C) were synthesized for the first time from highly available algal biomass of chlorella. The results showed that all the M(Fe,Co,Cu) N/P C catalysts exhibited excellent electrocatalytic performance for ORR. Especially, Fe N/P C obtained a half wave potential of 0.852 V (vs RHE) and a limiting current density of 4.4 mA cm−2, which are comparable to those of commercial 10% Pt/C catalyst (E 1/2 = 0.815 V, J d = 4.4 mA cm−2). In addition, Fe N/P C presents outstanding long-term stability and methanol resistance. A simple direct glucose fuel cell was assembled to further evaluate the catalytic ability of Fe N/P C. The fuel cell equipped with a Fe N/P C cathode achieved a peak power density of 30.53 W · m − 2 under ambient condition, which is superior to that with a 10% Pt/C cathode. This investigation provides a readily achievable route based on function-oriented fortification towards development of cost efficient ORR catalysts for AFCs. Graphical abstract Image 1 Highlights • Sponge-like porous carbons synthesized from highly available algal biomass. • Fe N/P C exhibited excellent electrocatalytic performance for ORR in DGAFC. • Maximum power density of 30.53 W/m2 was achieved under ambient condition. • The performance Fe N/P C is superior to 10% Pt/C in the DGAFC. [ABSTRACT FROM AUTHOR]

Marine macroalgae are considered to be one of the most important biomass sources. They can grow rapidly under various conditions, leading to extensive algal blooms. In this work, a reusable solid-acid catalyst, silicotungstic acid, was used to treat the seaweed Enteromorpha prolifera. Under optimum conditions, 237.354 mg/g (23.735%) of total reducing sugar yield was obtained. The hydrolysate was used as the substrate for bioenergy production in an alkaline fuel cell, and the fuel cell achieved the maximum power density of 6.616 W/m2 under the condition of 3 M KOH and 8.572 mg/mL reducing sugar in hydrolysate, which is higher than any other reported algae-fed fuel cells. [ABSTRACT FROM AUTHOR]

Low-cost and highly active catalyst for oxygen reduction reaction is of great importance in the design of alkaline fuel cells. In this work, Cu 2 O-Cu composite catalyst has been fabricated by a facile laser-irradiation method. The addition of Cu 2 O-Cu composite in activated carbon air-cathode greatly improves the performance of the cathode. Our results indicate the enhanced performance is likely attributed to the synergistic effect of high conductivity of Cu and the catalytic activity of Cu 2 O towards the oxygen reduction reaction. Furthermore, an alkaline fuel cell equipped with the composite air-cathode has been built to turn banana peels into electricity. Peak power density of 16.12 W m −2 is obtained under the condition of 3 M KOH and 22.04 g L −1 reducing sugar, which is higher than other reported low-temperature direct biomass alkaline fuel cells. HPLC results indicate the main oxidation products in the alkaline fuel cell were small organic acids. [ABSTRACT FROM AUTHOR]

A refuelable glucose alkaline fuel cell (AFC) is constructed by immobilizing methyl viologen (MV) on an activated carbon-nickel foam (AC/Ni) anode. The AFC exhibits a peak power density of 23.58 ± 0.83 Wm −2 at room temperature, which is more than 3 folds than that of non-immobilized control. Electrochemical impedance spectroscopy (EIS) investigations demonstrate that the internal resistance of the anode is remarkably decreased after MV immobilization. Surface morphology and composition of the anodes are characterized by field-emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDS). Spectroscopic studies indicate that the immobilized MV is stable at alkaline conditions. The AFC is discharged through a 100 Ω external resistor for 628 hours and a specific capacity of 244.01 mAh g −1 is obtained. Furthermore, the ability to refuel of the fuel cell is tested through multiple refuelling cycles. The refuelable glucose AFCs may provide a new realm to use carbohydrate as feedstocks for portable power sources and create an affordable pathway to renewable power. [ABSTRACT FROM AUTHOR]

The goal of this work was to develop a method for the direct power generation using macroalgae Enteromorpha prolifera . The process conditions for the saccharification of macroalgae were optimized and a type of alkaline fuel cell contained no precious metal catalysts was developed. Under optimum conditions (170 °C and 2% hydrochloric acid for 45 min), dilute acid hydrolysis of the homogenized plants yielded 272.25 g reducing sugar/kg dry algal biomass. The maximum power density reached 3.81 W/m 2 under the condition of 3 M KOH and 18.15 g/L reducing sugar in hydrolysate, higher than any other reported algae-fed fuel cells. This study represents the first report on direct electricity generation from macroalgae using alkaline fuel cells, suggesting that there is great potential for the production of renewable energy using marine biomass. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we developed a single-compartment direct cellulose alkaline fuel cell by using nickel foam as the anode and methyl viologen as an electron transfer catalyst. The maximum power density of the fuel cell at optimal conditions is 450 mW m−2. High-performance liquid chromatography detected short-chain aliphatic carboxylic acids in the oxidation products. Using common reed and red algae as fuels, the fuel cell achieved maximum power densities of 295 mW m−2 and 154 mW m−2, respectively. [Copyright &y& Elsevier]

Sugar has the potential to create enough energy to power mobile electronics. Various sugar-powered fuel cells have been reported, however, most of them used pure glucose as substrate and enzymes/noble metals as catalysts. In this work, an alkaline fuel cell with cheap catalysts were constructed, and different sweet drinks were used as fuels for power generation. The influence of different substrates on the electrochemical performance was characterized under the controlled conditions. Our experimental results showed that the fuel cell fueled with carbonated soft drinks had the best performance under the conditions of 99.95 g/L chemical oxygen demand and 3M KOH. The power densities of the fuel cell fueled with different substrates decreased in the order of Pepsi (33.41 W/m2) > Sprite (28.38 W/m2) > apple juice (20.63 W/m2) > Coca (16.31 W/m2) > pear juice (15.31 W/m2) > orange juice (12.75 W/m2), which was consistent with linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) analysis. This is the first report on alkaline fuel cell (AFC) performance using different sweet drinks as substrate. These values are more than 10 times higher than those of reported microbial fuel cells. Our findings demonstrated that sweet drinks fueled alkaline fuel cells can be a promising energy source for low-power electronics. [ABSTRACT FROM AUTHOR]