To improve the efficiency of overall water splitting, highly active and stable bifunctional electrocatalysts are highly desirable. Herein, we fabricated mixed Ni-Co phosphides (NiCo-P) as bifunctional catalysts for overall water splitting. Structural characterizations indicated that the NiCo-P catalysts (0 > x > 1) exhibited hierarchical yolk-shelled morphologies, with a total diameter of 1-2 μm. Interestingly, the shell was assembled by numerous nanosheets with a thickness less than 10 nm. The electrochemical measurements indicated that the NiCo-P catalysts (0 < x < 1) showed significantly enhanced OER and HER activities in comparison to the pure Ni-P and Co-P catalysts, and the highest OER and HER activities were achieved as x = 0.31. To drive a current density of 10 mA cm, the NiCo-P catalyst required an overpotential of 266 mV for OER and 96 mV for HER, respectively. The alkaline water electrolyzer with the NiCo-P catalysts as the cathode and anode catalysts required a cell voltage of ca. 1.59 V to achieve a current density of 10 mA cm, which was comparable to the integrated performance of commercial Pt/C and IrO. Furthermore, the electrolyzer assembled by the bufictional electrocatalysts showed a more stable performance than one assembled by commercial Pt/C and IrO operated at the simialr current density. The superior activity and long-term stability demonstrate that the hierarchical mixed Ni-Co phosphides have promising potential for application in large-scale water splitting.

Animal fats and partially hydrogenated vegetable oils (PHVO) have preferentially been used for deepfrying of food because of their relatively high oxidative stability compared to natural vegetable oils. However, animal fats and PHVO are abundant sources of saturated fatty acids and trans fatty acids, respectively, both of which are detrimental to human health. Canola (Brassica napus) is the primary oilseed crop currently grown in Australia. Canola quality Indian mustard (Brassica juncea) is also being developed for cultivation in hot and low-rainfall areas of the country where canola does not perform well. A major impediment to using these oils for deep-frying is their relatively high susceptibility to oxidation, and so any processing interventions that would improve the oxidative stability would increase their prospects of use in commercial deep-frying. The oxidative stability of both B. napus and B. juncea crude oils can be improved dramatically by roasting the seeds (165 7C, 5 min) prior to oil extraction. Roasting did not alter the fatty acid composition or the tocopherol content of the oils. The enhanced oxidative stability of the oil, solventextracted from roasted seeds, is probably due to 2,6-dimethoxy-4-vinylphenol produced by thermal decarboxylation of the sinapic acid naturally occurring in the canola seed.

Development of noble-metal-free and active electrocatalysts is crucial for the oxygen evolution reaction (OER) in the water-splitting process. Herein, crystal Co x B catalysts (x = 1–3) of the OER are fabricated by a ball-milling method. Among these Co x B catalysts, Co2B exhibits the best OER activity, with a current density of 10 mA cm–2 at an overpotential of 287 mV in 1 M KOH solution. Such OER activity of Co2B is favorably comparable to that of the commercial IrO2 and most recently reported OER catalysts. Furthermore, the Co2B catalyst exhibits excellent stability with a stable current density of 50 mA cm–2 over 12 h of continuous electrolysis operation. X-ray photoelectron spectroscopy and cyclic voltammetry demonstrate that the B in Co x B makes oxidation easier, leading to their enhanced OER activities in comparison to metal Co. In addition, the Co2B electrocatalyst also exhibits high activity in the hydrogen evolution reaction; thus, the catalyst can be used as a bifunctional catalyst for full water splitting.

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