Periodically patterned MoS2/TiO2 heterostructures were rationally designed as nonmetal plasmonic photocatalysts for highly efficient hydrogen evolution.

has been widely regarded as one of the most promising energy conversion and storage technologies to meet the growing energy demands of largescale application for electric vehicles and other electricity-related devices. [1] The two prominent reactions involved in ZABs are oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), both of which determine the practical performance of ZABs. Thus, the use of highly efficient and stable electrocatalysts as air electrodes is of paramount significance for facilitating the sluggish ORR and OER, thereby attaining high power and long operating lifetime performance for ZABs. Typically, platinum group metals (PGM) are most favorable ORR and OER catalysts displaying the absolute superiority of catalytic activity. However, the high cost, poor stability/durability, and low poison resistance of PGM have been the primary barriers that hamper widespread commercialization of ZABs. [1b,2] With decades of intensive effort in developing the cost-effective catalysts that possess remarkable catalytic performance, a new generation of PGM-free electrocatalystsThe oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in zinc-air batteries (ZABs) require highly efficient, cost-effective, and stable electrocatalysts as alternatives to high cost and low poison resistant platinum group metals (PGM) catalysts. Although nitrogen-doped carbon nanotube (NCNT) arrays are now capable of catalyzing ORR efficiently, their hydrophobic surface and base-growth mode are found to limit the catalytic performance in the practical ZABs. Here, the concept of an apically dominant mechanism in improving the catalytic performance of NCNT by precisely encapsulating CoNi nanoparticles (NPs) within the apical domain of NCNT on the Ni foam (denoted as CoNi@NCNT/NF) is demonstrated. The CoNi@NCNT/NF exhibits a more excellent catalytic performance toward both ORR and OER than that of traditional NCNT derived from the base-growth method. The ZAB coin cell using CoNi@NCNT/NF as an air electrode shows a peak power density of 127 mW cm −2 with an energy density of 845 Wh kg Zn −1 and rechargeability over 90 h, which outperforms the performance of PGM catalysts. Density functional theory calculations reveal that the ORR catalytic performance of the CoNi@NCNT/NF is mainly attributed to the synergetic contributions from NCNT and the apical active sites on NCNT near to CoNi NPs.

Carbon nitride (g-C 3 N 4 ) materials are electroactivated for oxygen reduction (ORR) and oxygen evolution (OER) reactions when they are supported by conductive carbons. However, the electrocatalytic process on semiconductor-based heterostructures such as carbon-supported g-C 3 N 4 still suffers from a huge energy loss because of poor electron mobility. Here, we demonstrated a concept that the conjugation of g-C 3 N 4 with crystalline carbon can improve the in-plane electron mobility and make interior triazine units more electro-active for ORR and OER. As a result, the Co metal coordinated g-C 3 N 4 with crystalline carbons (Co− C 3 N 4 /C) showed a remarkable electrocatalytic performance toward both ORR and OER. For example, it displayed an onset potential of 0.95 V for ORR and an overpotential of 1.65 V for OER at 10 mA cm −2 , which are comparable and even better than those of benchmark Pt, RuO 2 , and other carbon nitride-based electrocatalysts. As a proof-of-concept application, we employed this catalyst as an air electrode in the rechargeable aluminum-air battery, which showed more rechargeable and practicable than those of Pt/C and RuO 2 catalysts in two-electrode coin battery. The characterization results identified that the good performance of Co−C 3 N 4 /C was primarily attributed to the enhanced in-plane electron mobility by crystalline carbon conjugation and the Co-coordinated g-C 3 N 4 along with nitrogen-doped carbons.

efficient and earth-abundant catalysts have been successfully developed including nitrogen-doped carbon materials that possess promising electrocatalytic performance for ORR and OER. [6][7][8][9][10] However, it remains challenging for nitrogen-doped carbon materials to achieve competitive performance to precious metal catalysts due to low nitrogen concentration.Graphitic carbon nitrides (g-C 3 N 4 ) have shown promising performance to replace nitrogen-doped carbon as a highly efficient catalyst, owing to its ultrahigh nitrogen content (theoretically estimated to be ≈60%) and easily tailored structure. [11][12][13][14][15] It is also well-known that the electrocatalytic performance is determined by catalyst structure and accessibility of active sites. It is of significant importance to maximize the electrochemical surface area to better facilitate the transport of reactants (OH − and O 2 ), and therefore enhance catalytic activity. [16][17][18] For this aim, various methods have been reported in preparation of porous g-C 3 N 4 . Conventionally, rigid templates (SiO 2 , Al 2 O 3 , and ZnO) are used to fabricate porous g-C 3 N 4 , [19,20] which can effectively improve accessibility and catalytic activity of g-C 3 N 4 . However, these rigid template-based synthesis methods are complicated, involving several steps such as template formation, template dispersion, template removal, and catalyst purification. These time-consuming processes increase the fabrication cost and can even damage the g-C 3 N 4 active sites during template removal by the use of strong acidic or basic etching. Addressing these challenges will require facile and strategic developments to synthesize porous g-C 3 N 4 without using templates.Herein, we developed a top-down and template-free strategy for the fabrication of porous g-C 3 N 4 (PCN) by controlled pyrolysis of Co 2+ /melamine networks in O 2 atmosphere. After mixing PCN with graphene oxide (GO) and thermal treating in sulfur atmosphere, CoS x @PCN/rGO catalyst was synthesized. The developed CoS x @PCN/rGO catalyst exhibited outstanding electrocatalytic activity and stability toward both OER and ORR. The CoS x @PCN/rGO also showed long cyclability as an air electrode in a zinc-air battery system, outperforming Pt and other precious metal electrocatalysts. The remarkable electrocatalytic performance of CoS x @PCN/rGO is attributed to the internally accessible nitrogen sites and the facilitated transport of intermediates in the porous structure.A typical synthesis route of PCN is schematically depicted in Figure 1a: First, cobalt(II) nitrate hexahydrate was mixed with Porous carbon nitride (PCN) composites are fabricated using a top-down strategy, followed by additions of graphene and CoS x nanoparticles. This subsequently enhances conductivity and catalytic activity of PCN (abbreviated as CoS x @PCN/rGO) and is achieved by one-step sulfuration of PCN/ graphene oxides (GO) composite materials. As a result, the as-prepared CoS x @PCN/rGO catalysts display excellent activity and stability towa...

Conductive polymer composites (CPCs) containing nanoscale conductive fillers have been widely studied for their potential use in various applications. In this paper, polypyrrole (PPy)/polydopamine (PDA)/silver nanowire (AgNW) composites with high electromagnetic interference (EMI) shielding performance, good adhesion ability and light weight are successfully fabricated via a simple in situ polymerization method followed by a mixture process. Benefiting from the intrinsic adhesion properties of PDA, the adhesion ability and mechanical properties of the PPy/PDA/AgNW composites are significantly improved. The incorporation of AgNWs endows the functionalized PPy with tunable electrical conductivity and enhanced EMI shielding effectiveness (SE). By adjusting the AgNW loading degree in the PPy/PDA/AgNW composites from 0 to 50 wt%, the electrical conductivity of the composites greatly increases from 0.01 to 1206.72 S cm, and the EMI SE of the composites changes from 6.5 to 48.4 dB accordingly (8.0-12.0 GHz, X-band). Moreover, due to the extremely low density of PPy, the PPy/PDA/AgNW (20 wt%) composites show a superior light weight of 0.28 g cm. In general, it can be concluded that the PPy/PDA/AgNW composites with tunable electrical conductivity, good adhesion properties and light weight can be used as excellent EMI shielding materials.