Maximizing the Pt utilization is important for the widescale implementation of Pt-based hydrogen evolution reaction (HER) electrocatalysts, owing to the scarcity of Pt. Here, three-component heterostructured HER catalysts with ultrahigh Pt mass activity in which hollow PtCu alloy nanospheres are supported on an array of WO 3 on Cu foam, are reported. It has been pointed out that the use of Pt counter electrode in a three-electrode configuration in evaluating catalysts' HER performances in acidic media carries the risk of contaminating the working electrode in previous reports. Here, the authors rationally utilize this "contaminating" to "activate" low-HER-activity materials, maximizing the Pt utilization. As a result, ultrahigh Pt mass activity is achieved, that is 1.35 and 10.86 A mg −1 Pt at overpotentials of 20 and 100 mV, respectively, 27 and 13 times higher than those of commercial Pt/C catalysts, outperforming some state-of-the-art Pt-single-atom catalysts. The hollow sphere structure and PtCu alloying increase the number and reactivity of active sites. Density function calculations and electrochemical experiments reveal that the synergy between WO 3 and Pt is also responsible for the high HER activity where the hydrogen spillover effect triggers the Volmer-Heyrovsky mechanism and promotes the rapid removal of H * from Pt to re-expose the active sites.

The oxygen evolution reaction (OER) is a key reaction in water splitting and metal–air batteries, and transition metal hydroxides have demonstrated the most electrocatalytic efficiency. Making the hydroxides thinner for more surface commonly fails to increase the active site number, because the real active sites are the edges. Up to now, the overpotentials of most state‐of‐the‐art OER electrocatalysts at a current density of 10 mA cm−2 (η10) are still larger than 200 mV. Herein, a novel design of mesoporous single crystal (MSC) with an Fe‐rich skin to boost the OER is shown. The edges around the mesopores provide lots of real active sites and the Fe modification on these sites further improves the intrinsic activity. As a result, an ultralow η10 of 185 mV is achieved, and the turnover frequency based on Fe atoms is as high as 16.9 s−1 at an overpotential of 350 mV. Moreover, the catalyst has an excellent catalytic stability, indicated by a negligible current drop after 10 000 cyclic voltammetry cycles. The catalyst enables Zn–air batteries to run stably over 270 h with a low charge voltage of 1.89 V. This work shows that MSC materials can provide new opportunities for the design of electrocatalysts.

The highly efficient bifunctional catalyst for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is the key to achieving high-performance rechargeable Zn–air batteries. Non-precious-metal single-atom catalysts (SACs) have attracted intense interest due to their low cost and very high metal atomic utilization; however, high-activity bifunctional non-precious-metal SACs are still rare. Herein, we develop a new nanospace-confined sulfur–enamine copolymerization strategy to prepare a new type of bifunctional Mo SACs with O/S co-coordination (Mo-O2S2-C) supported on the multilayered, hierarchically porous hollow tubes. The as-prepared catalyst can not only expose more active sites and facilitate mass transfer due to their combined micropores, mesopores, and macropores but also have the S/O co-coordination structure for optimizing the adsorption energies of the ORR intermediates. Its ORR activity is among the highest, and it shows a low overpotential of 324 mV for the OER at 10 mA cm–2 in all of the reported Mo-based catalysts. When assembled in a Zn–air battery, it exhibits a high maximal power density of 197.3 mW cm–2 and a long service life of 50 hours, superior to those of Zn–air batteries using commercial Pt/C+IrO2.

In the genetic improvement of livestock and poultry, residual feed intake (RFI) is an important economic trait. However, in sheep, the genetic regulatory mechanisms of RFI are unclear. In the present study, we measured the feed efficiency (FE)-related phenotypes of 137 male Hu lambs, and selected six lambs with very high (n = 3) and very low (n = 3) RFI values and analyzed their liver transcriptomes. A total of 101 differentially expressed genes were identified, of which 40 were upregulated and 61 were downregulated in the low-RFI group compared with that in the high-RFI group. The downregulated genes were mainly concentrated in immune function pathways, while the upregulated genes were mainly involved in energy metabolism pathways. Two differentially expressed genes, ADRA2A (encoding adrenoceptor alpha 2A) and RYR2 (ryanodine receptor 2), were selected as candidate genes for FE and subjected to single nucleotide polymorphism scanning and association analysis. Two synonymous mutations, ADRA2A g.1429 C > A and RYR2 g.1117 A > C, were detected, which were both significantly associated with the feed conversion rate. These findings provide a deeper understanding of the molecular mechanisms regulating FE, and reveal key genes and genetic variants that could be used to genetically improve FE in sheep.

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