Selective electrocatalytic NH3 synthesis using Li intercalated 1T-MoS2.

A battery with high energy density, large capacity, long cyclability, safety, and flexibility is desired to not only power small electronic devices but also provide solutions to large-scale energy storage management. In this work, a hybrid battery of Zn–Ag and Zn–air (Zn–Ag/air) has been successfully fabricated in which Ag acted as an active material at the charging state and as an oxygen reduction reaction catalyst at the discharging state. In traditional zinc air batteries, Ag was used as a catalytic material only. In this work, sufficient amounts of Ag nanoparticles were covered onto stainless steel wire screen via a facile electrodeposition procedure as not only catalytic materials but also active redox materials. The rigid hybrid battery delivered two discharging plateaus at 1.5 and 1.1 V in which the higher one was attributed to reduction of Ag2O to Ag and the lower one resulted from Ag-assisted oxygen reduction reaction. The cyclability test showed that the Coulombic efficiency retained higher than 85% after 1700 cycles. Furthermore, the Zn–Ag/air hybrid battery was also able to be packed in a pouch cell and demonstrated high flexibility and rechargeable capability. Overall results indicate that the hybrid battery possesses both advantages of Zn–Ag and Zn–air batteries with improved discharging potential and enhanced storage capacity.

Intensive energy demand urges state-of-the-art rechargeable batteries. Rechargeable aluminum-ion batteries (AIBs) are promising candidates with suitable cathode materials. Owing to high abundance of carbon, hydrogen, and oxygen and rich chemistry of organics (structural diversity and flexibility), small organic molecules are good choices as the electrode materials for AIB. Herein, a series of small-molecule quinone derivatives (SMQD) as cathode materials for AIB were investigated. Nonetheless, dissolution of small organic molecules into liquid electrolytes remains a fundamental challenge. To nullify the dissolution problem effectively, 1,4-benzoquinone was integrated with four bulky phthalimide groups to form 2,3,5,6-tetraphthalimido-1,4-benzoquinone (TPB) as the cathode materials and assembled to be the AI/TPB cell. As a result, the Al/TPB cell delivered capacity as high as 175 mA h/g over 250 cycles in the urea electrolyte system. Theoretical studies have also been carried out to reveal and understand the storage mechanism of the TPB electrode.

Nitrate (NO3 –) reduction reaction (NtRR) is considered as a green alternative method for the conventional method of NH3 synthesis (Haber–Bosch process), which is known as a high energy consuming and large CO2 emitting process. Herein, the copper nanodendrites (Cu NDs) grown along with the {200} facet as an efficient NtRR catalyst have been successfully fabricated and investigated. It exhibited high Faradaic efficiency of 97% at low potential (−0.3 V vs RHE). Furthermore, the 15NO3 – isotope labeling method was utilized to confirm the formation of NH3. Both experimental and theoretical studies showed that NtRR on the Cu metal nanostructure is a facet dependent process. Dissociation of NO bonding is supposed to be the rate-determining step as NtRR is a spontaneously reductive and protonation process for all the different facets of Cu. Density functional theory (DFT) calculations revealed that Cu{200} and Cu{220} offer lower activation energy for dissociation of NO compared to that of Cu{111}.

Hydrogen evolution reaction (HER) from electrocatalytic water splitting is a prospective technology to supply clean energy with low environmental impact for the future. In this work, plasmonic silver nanocubes (AgNCs) with (100) facet and silver nanooctahedra (AgNOs) with (111) facet were applied as the light-harvesting catalysts for enhancing hydrogen production in the plasmon-activated HER electrochemical system. As light harvesters, AgNCs and AgNOs can efficiently absorb light ranging from ultraviolet to near-infrared to generate hot electrons for facilitating electrocatalytic HER. Both AgNCs and AgNOs revealed the light-harvesting capability to improve HER activities with laser irradiation. Moreover, the current densities of AgNOs with (111) facet were higher than those of AgNCs with (100) facet for electrocatalytic HER under irradiations with three different laser wavelengths. The density functional theory (DFT) simulations revealed that the adsorption energy of the surfaces followed the order Ag(111) < Ag(100), indicating that hydrogen could be easily desorbed on the Ag(111) surface for HER. Combination of the experimental HER results and DFT simulations expressed that AgNOs with (111) facet were the excellent light harvesters in this study. Based on the DFT simulations of the H-Ag(111) and H-Ag(100) systems, the findings could be extended to other plasmon-enhanced HER electrochemical systems and could enable electrocatalysts to be designed at the atomic level.