Ba-Ri Wulan

Au Sub‐Nanoclusters on TiO2 toward Highly Efficient and Selective Electrocatalyst for N2 Conversion to NH3 at Ambient Conditions

As the NN bond in N2 is one of the strongest bonds in chemistry, the fixation of N2 to ammonia is a kinetically complex and energetically challenging reaction and, up to now, its synthesis is still heavily relying on energy and capital intensive Haber-Bosch process (150-350 atm, 350-550 °C), wherein the input of H2 and energy are largely derived from fossil fuels and thus result in large amount of CO2 emission. In this paper, it is demonstrated that by using Au sub-nanoclusters (≈0.5 nm ) embedded on TiO2 (Au loading is 1.542 wt%), the electrocatalytic N2 reduction reaction (NRR) is indeed possible at ambient condition. Unexpectedly, NRR with very high and stable production yield (NH3 : 21.4 µg h-1 mg-1cat. , Faradaic efficiency: 8.11%) and good selectivity is achieved at -0.2 V versus RHE, which is much higher than that of the best results for N2 fixation under ambient conditions, and even comparable to the yield and activation energy under high temperatures and/or pressures. As isolated precious metal active centers dispersed onto oxide supports provide a well-defined system, the special structure of atomic Au cluster would promote other important reactions besides NRR for water splitting, fuel cells, and other electrochemical devices.

Anchoring and Upgrading Ultrafine NiPd on Room‐Temperature‐Synthesized Bifunctional NH2‐N‐rGO toward Low‐Cost and Highly Efficient Catalysts for Selective Formic Acid Dehydrogenation

Hydrogen is widely considered to be a sustainable and clean energy alternative to the use of fossil fuels in the future. Its high hydrogen content, nontoxicity, and liquid state at room temperature make formic acid a promising hydrogen carrier. Designing highly efficient and low-cost heterogeneous catalysts is a major challenge for realizing the practical application of formic acid in the fuel-cell-based hydrogen economy. Herein, a simple but effective and rapid strategy is proposed, which demonstrates the synthesis of NiPd bimetallic ultrafine particles (UPs) supported on NH2 -functionalized and N-doped reduced graphene oxide (NH2 -N-rGO) at room temperature. The introduction of the NH2 N group to rGO is the key reason for the formation of the ultrafine and well-dispersed Ni0.4 Pd0.6 UPs (1.8 nm) with relatively large surface area and more active sites. Surprisingly, the as-prepared low-cost NiPd/NH2 -N-rGO dsiplays excellent hydrophilicity, 100% H2 selectivity, 100% conversion, and remarkable catalytic activity (up to 954.3 mol H2 (mol catalyst)-1 h-1 ) for FA decomposition at room temperature even with no additive, which is much higher than that of the best catalysts so far reported.

Efficient visible-light-driven hydrogen generation from water splitting catalyzed by highly stable CdS@Mo2C–C core–shell nanorods

Sunlight-driven water splitting using light-absorbing semiconductor-based materials is an ongoing strategy to overcome the world-wide environmental pollution and energy crisis. The construction of core–shell-type nanostructures by coupling of the earth-abundant hydrogen generation catalyst Mo2C to the good photoabsorber CdS may be the best combination for photocatalytic hydrogen generation reaction. Thus, in this work, core–shell nanorods consisting of a CdS core and a Mo2C–C shell have been designed and synthesized for the first time. The as-prepared CdS@Mo2C–C nanorods display an excellent hydrogen generation rate of 17.24 mmol h−1 g−1 relative to pure CdS, which may result from the unique one-dimensional nanostructure, the strong interfacial interaction between the core and shell materials, as well as the broadened visible-light absorption range. Whats more, the existence of C layers in the core–shell nanorods can facilitate transfer of the photogenerated holes to the outer shell of Mo2C–C, and thus protect the inner CdS from photocorrosion to finally achieve high photostability of the catalyst.

Non-noble-metal bismuth nanoparticle-decorated bismuth vanadate nanoarray photoanode for efficient water splitting

Sunlight-driven photoelectrochemical (PEC) water splitting using earth-abundant semiconductor-based materials offers one promising strategy to produce attainable and sustainable carbon free energy. Herein, we demonstrate for the first time that a heterojunction nanostructure of a Bi/BiVO4 photoanode is fabricated by directly coupling semimetal Bi nanoparticles to BiVO4 nanoarrays, showing excellent water oxidation performance. The as-obtained photoanode exhibits a remarkable photocurrent density of 1.96 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (vs. RHE) under AM 1.5G (100 mW cm−2) irradiation, which is approximately 2-fold higher than that of the pristine BiVO4. Based on the detailed analyses of J–V, i–t, M–S and EIS plots, the reason for the high photocurrent density of Bi/BiVO4 can be attributed to the improved charge separation efficiency, the enhanced hole injection efficiency and the suppressed back reaction of water oxidation.

Non-noble metals applying to solar water splitting

The generation of hydrogen (H2) induced by solar water splitting over semiconductors has been regarded as one of the most promising strategies for providing clean and renewable energy sources for future energy sustainability. The key to achieving high solar-to-chemical-energy conversion efficiency is the design of efficient structures with high charge separation and transportation; thus, the development of inexpensive and functional nanomaterials has become quite necessary. Photocatalysts based on non-noble metals have great potential as substitutes for noble metal-based catalysts for H2 generation from photocatalytic (PC) and/or photoelectrochemical (PEC) water splitting. In this review, we present the recent progress on non-noble metal-based nanostructures using in PC and/or PEC water splitting and reveal their underlying roles in affecting the behavior of charge carriers in specific reactions. This review should bring new insight and inspire further innovative work on designing non-noble metals involved in solar water splitting.