[en] Cobalt sulfide materials are wildly investigated in oxygen evolution reaction (OER). In order to further decrease the cost of the catalysts, cobalt-copper-iron trimetal sulfides (CoCuFe-S) are designed and successfully fabricated via a simple hydrothermal method following a thermal treatment. CoCuFe-S has a three-dimensional nanostructure, which is assembled by numerous nanosheets. Three components are uniformly distributed in the composite. CoCuFe-S with different ratios are employed as OER catalysts and compared with pure Co₉S₈, CuS and FeS. The optimal CoCuFe-S-8 catalyst exhibits high and robust activity for OER with a small overpotential of 0.30 V at current density of 10 mA cm⁻² and a low Tafel slope of 79 mV·dec⁻¹. The turnover frequency is 0.27 s⁻¹ and the mass activity is 114 A g⁻¹ at overpotential of 0.30 V, even better than the commercial RuO₂. In addition, CoCuFe-S-8 catalyst showed long-term durability under 1 M KOH solution. The excellent OER performance may result from the synergistic effect among the three sulfides. The introduction of FeS and CuS are beneficial for the formation of Co₉S₈, increasing the conductivity of the catalyst and decreased the adsorption of the oxygen atoms on Co atom.

[en] Highlights: • The ultra-stretchable bionic sensors based on FLM were integrated on a SCR to realize bionic sensing. • The TTS was sensitive to the unknown stimulus of various materials. The RSS was sensitive to the bending of SCR. • Closed-loop control enabled SCR to achieve intelligent sensing and automatic motion. Soft robots have significant advantages in terms of flexibility and adaptability, leading to potential applications in the bionics field. Inspired by the caterpillars in nature, this work proposed a soft caterpillar robot (SCR) by integrating two types of ultra-stretchable bionic sensors on a dual air-chamber pneumatic network structure. In order to realize self-powered tactile sensing, four triboelectric nanogenerator tactile sensors (TTSs) based on functional liquid metal (FLM) with thorny-structured bionic whiskers are developed and attached on the SCR. Meanwhile, two ultra-stretchable resistive strain sensors (RSSs) by using FLM are covered as the bionic skin to sense self-body deformation of the SCR. The TTS has a fast response time of 0.03 s and a minimum perception of 0.05 kPa, which can be very sensitive to the unknown stimulus of various materials. The RSS with a relatively high sensitivity of 2.94 and small hysteresis of 1.42% possess the ultra-stretchable ability of 180% strain, which helps to adapt and adjust its own body bending and crawling. The biological perception capabilities of the SCR play a crucial role in mimicking bionic actions and response in an unknown environment, such as escaping from unexpected attacks as well as adaptive crawling through an unknown tunnel environment.

[en] Recently, much attention has focused on less platinum alternative materials serving as the counter electrode material for dye-sensitized solar cells, while platinum itself has a lot of room for improvement. Herein, we introduce the earth-abundant silicon and combine it with Pt nanoparticles as the counter electrode in dye-sensitized solar cells to enlarge surface area and enhance the activity of Pt. Si-H bonds can reduce metal ions and enable small metal nanoparticles grown on the surface of silicon nanowires, which can effectively prevent metal nanoparticles from agglomeration in the catalysis. The density functional theory (DFT) calculation shows that the adsorption energy of I atom on the Pt/Si interface is −0.8 eV, which is the optimal adsorption energy for triiodide reduction, indicating that Pt/Si is a perfect material for the counter electrode. The electrochemical characterizations and the photocurrent-voltage performance experimentally confirm that Pt/SiNW is a better counter electrode material than other metal/SiNW composites and Pt, which is in accordance with DFT calculations. The power conversion efficiency of device based on the Pt/SiNW electrode is higher than that of the device based on Pt (8.23% vs.7.93%).

[en] Though noble metals play a key role in the clean energy research, their wide practical applications have been limited by the high cost and the scarce natural reserves. It is significant to decrease their usage and increase the active sites in the catalysis. Herein, Rh nanocrystals were grown on the surface of silicon quantum dots with the help of SiH bonds to obtain RhSi composites, which combined with carbon quantum dots to fabricate RhSiC nanocomposites. The silicon quantum dots limited the size of Rh and prevented the aggregation. The addition of carbon quantum dots greatly increased the electron transportation during the catalytic process. When the RhSiC nanocomposites were applied as electrocatalysts for hydrogen evolution reaction (HER), the optimal one exhibits Pt-like HER performance (low Tafel slope of 26 mV·dec^-1 and long-term stability) with the content of noble metal less than half of that in 20 wt% Pt/C. This work could put forward an effective avenue to develop high efficient and affordable electrochemical catalysts for HER.