ZnO monolayer-supported single atom catalysts for efficient electrocatalytic hydrogen evolution reaction.

Uranium is an essential element as both fission fuel and radioactive waste. Therefore, the recovery of uranium is of great importance. Here, an internal enhanced photocatalytic fuel cell (IEPFC) system is proposed to achieve high‐efficiency uranium extraction performance through the hydrogen evolution reaction (HER) process. An asymmetric Co 1 N 3 P 1 , derived from phosphorated ZIF‐67 grown on carbon felt (Co 1 N 3 P 1 C/CF), is utilized as a cathode and demonstrates excellent HER performance. A front FTO glass‐based TiO 2 nanorod (TNR) film and a rear‐placed Si photovoltaic cell (Si PVC) serve as an integrated photoanode. Thanks to the high HER performance of the Co 1 N 3 P 1 cathode and the enhanced internal drive of the photoanode, both the uranium recovery efficiency and the organic tetracycline (TC) degradation rate can reach 100% within 40 min of illumination. X‐ray absorption near‐edge structure (XANES) and density functional theory (DFT) calculations reveal that the Co 1 N 3 P 1 possesses a positive synergistic effect between HER and uranium recovery. This enhancement is due to the modified electronic structure resulting from the incorporation of P, and the robust adsorption between U and OH * promoted by electron transfer interactions between U and N and P. This work opens a new opportunity for the recovery of uranium from the complex water bodies.

Mo isolated single atoms on S, N-codoped carbon as efficient catalyst for hydrogen evolution reaction: A theoretical evaluation

Low-cost single-atom transition metals on two-dimensional SnO nanosheets for efficient hydrogen evolution catalysis in all pH-range

Well‐dispersed PtCu alloy nanoparticles (NPs) with a diameter of only ≈2 nm encapsulated in carbon nanofibers (CNFs) are synthesized using electrospinning technology followed by a graphitization process in a chemical vapor deposition furnace. Distinctly, even with a small amount of Pt, the PtCu/CNFs‐1:2 catalyst possesses outstanding hydrogen evolution reaction (HER) activity, including small overpotential, long‐term stability, and a high exchange current density as well as large double layer capacitance (Cdl). The excellent HER performance of the PtCu/CNFs‐1:2 catalyst is attributed to the synergistic interaction between Pt and Cu, the uniform distribution of the alloy NPs and the use of CNFs with 3D architectures. This development may provide a simple, efficient, and green synthesis method to design bi‐ or multimetal alloys for use as the cathode electrocatalysts for the HER or other electrocatalytic devices.

Fe-B alloy coupled with Fe clusters as an efficient cocatalyst for photocatalytic hydrogen evolution

Quasi-atomic-scale platinum anchored on porous titanium nitride nanorod arrays for highly efficient hydrogen evolution

The hydrogen evolution reaction (HER) is crucially important for water splitting, for which platinum (Pt) has been considered the state-of-the-art electrocatalyst. Despite recent progress in non-Pt electrocatalysts, few Pt-free catalysts can compete against Pt in terms of HER activity particularly in alkaline solution. Here, we report a new efficient Pt-free HER catalyst – hybrid ruthenium cobalt phosphide (RuCoP) cluster where Ru exists in metallic chemical state in the hybrid. The unique hybridization allows electron transfer to take place from both Co and P to Ru, thereby significantly enhancing the hybrid’s HER activity. The as-synthesized RuCoP clusters demonstrate a considerably low overpotential (η) of 11 mV at -10 mA cm2 and a high turnover frequency (TOF) of 5.64 s-1 at η = 100 mV in 0.5 M H2SO4. Remarkably, even in alkaline solution (1.0 M KOH) the excellent HER performance of RuCoP remains, with a very low η 10 of 23 mV and exceptionally high TOF value of 3.85 s-1 at η = 100 mV. Moreover, the RuCoP catalysts show outstanding catalytic stability toward the HER in both acidic and alkaline solutions, superior to that of commercially available Pt/C catalysts. Figure 1

Asymmetrical radial strain energy strategy of M–N–SWCNT single atom catalysts for highly efficient hydrogen evolution: A high-throughput DFT study

Very recently, a type of two-dimensional $(2D)$ crystals, $M{\mathrm{Si}}_{2}{\mathrm{N}}_{4}(M=\mathrm{Mo},\mathrm{W})$, has been successfully synthesized in experiment [Y.-L. Hong et al., Science 369, 670 (2020)]. Here, using first-principles calculations, we systematically investigate the potential of two-dimensional $(2D)$ $\mathrm{M}{\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ as hydrogen evolution reaction (HER) catalysts, and propose two effective ways to trigger their HER activity. Our computations reveal that while the metal vacancies cannot activate the inertia planes for HER, $2D$ $\mathrm{M}{\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ with $N$ vacancy exhibits excellent HER performance. Especially for $2D$ $\mathrm{W}{\mathrm{Si}}_{2}{\mathrm{N}}_{4}$, the introduction of $N$ vacancy can yield an ideal value of hydrogen adsorption Gibbs free energy $(\mathrm{\ensuremath{\Delta}}{G}_{{\mathrm{H}}^{*}}=\ensuremath{-}0.02\phantom{\rule{0.16em}{0ex}}\mathrm{eV})$, even superior to that of Pt $(\mathrm{\ensuremath{\Delta}}{G}_{{\mathrm{H}}^{*}}=\ensuremath{-}0.09\phantom{\rule{0.16em}{0ex}}\mathrm{eV})$. Moreover, by high-throughput screening of $3d$, $4d$, and $5d$ transition metals, we find that introducing V/Fe/Nb/Tc/Ta atom into $2D$ $\mathrm{M}{\mathrm{Si}}_{2}{\mathrm{N}}_{4}$ can significantly trigger their HER activity. The underlying physics are discussed in detail. Our work not only highlights a family of potential HER electrocatalysts, but also provides feasible strategies for triggering their HER activity.

The development of nonprecious electrochemical catalysts for water splitting is a key step to achieve a sustainable energy supply for the future. Molybdenum disulfide (MoS2) has been extensively studied as a promising low‐cost catalyst for hydrogen evolution reaction (HER), whereas HER is only catalyzed at the edge for pristine MoS2, leaving a large area of basal plane useless. Herein, on‐surface self‐assembly is demonstrated to be an effective, facile, and damage‐free method to take full advantage of the large ratio surface of MoS2 for HER by using multiscale simulations. It is found that as supplement of edge sites of MoS2, on‐MoS2 M(abt)2 (M = Ni, Co; abt = 2‐aminobenzenethiolate) owns high HER activity, and the self‐assembled M(abt)2 monolayers on MoS2 can be obtained through a simple liquid‐deposition method. More importantly, on‐surface self‐assembly provides potential application for overall water splitting once the self‐assembled systems prove to be of both HER and oxygen evolution reaction activities, for example, on‐MoS2 Co(abt)2. This work opens up a new and promising avenue (on‐surface self‐assembly) toward the full exploitation of the basal plane of MoS2 for HER and the preparation of bifunctional catalysts for overall water splitting.

Ultrafine cobalt-ruthenium alloy nanoparticles induced by confinement effect for upgrading hydrogen evolution reaction in all-pH range

The hydrogen evolution reaction (HER) is a key chemical reaction as part of water splitting to produce clean hydrogen. Pt is the best catalyst for HER in acidic media, but its activity is greatly reduced under alkaline conditions. Therefore, improving the sluggish alkaline HER kinetics is urgently needed to achieve highly efficient hydrogen production by alkaline electrolyte membrane (AEM) water electrolysis. Herein, Pt nanocatalysts supported on Ni-Fe oxides were synthesized by a modified colloidal method, which exhibit approximately 4 times higher HER specific activity and more than 2 times higher mass activity compared to a commercial Pt/C catalyst in alkaline solution, showing the potential to reduce Pt loading by half on the cathode side of AEM water electrolyzers. The high HER activity corresponds to the large amount in the Ni-Fe oxide phase accompanied by a moderate hydrogen binding energy with Pt. Keeping Pt and Ni-Fe oxides in separate phases is more effective than forming a Pt-Ni-Fe alloy in improving HER activity. Experimental results and density functional theory calculations indicate that the NiFe oxide not only promotes water dissociation but also facilitates the hydrogen adsorption/desorption process on Pt, thereby accelerating the overall kinetics of alkaline HER. The identification of these electrocatalytic trends for metal/oxide modified Pt catalysts provides fundamental insights that can guide the design and synthesis of efficient alkaline HER catalysts for hydrogen production.

Nickel (Ni)-based nanomaterials have been intensively explored as promising noble-metal-free hydrogen evolution reaction (HER) electrocatalysts. Here, we report that uniform sea urchin-like NiSe nanofiber assemblies can be prepared on a large scale by a ternary mixed solvent strategy. The new NiSe exhibits very high HER activity in 0.5 M H2SO4, comparable to the best performance of the well-studied MoS2 catalysts. The Tafel slope of ∼64 mV per decade was observed for the sea urchin-like NiSe catalyst, suggesting that the Volmer–Heyrovsky HER mechanism presumably takes effect in the HER. Although the stability of such a NiSe nanofiber assembled nanostructure needs to be further improved, this study addresses the benefits and possibilities of using Ni-based chalcogenides to design high performance and low cost HER catalysts.

Exploring catalysts with low cost and excellent performance for the hydrogen evolution reaction (HER) is still a significant challenge. In this work, zeolitic imidazolate framework 8 (ZIF-8), hybridized with polyvinylpyrrolidone, was used to prepare Zn, Ni co-loaded N-doped porous carbon (ZnNi/NPC) via a straightforward absorption and pyrolysis process. The as-prepared ZnNi/NPC was used as a catalyst for the HER. This experiment showed that the porous structure and Ni doping have a significant influence on the HER activity of the catalyst. Compared with Zn/NC and Zn/NPC, ZnNi/NPC exhibits superior HER activity with an overpotential of 198 mV and a Tafel slope of 69.2 mV dec−1. ZnNi/NPC also shows excellent physical and chemical stability during the HER process. Considering the lower cost and excellent HER performance of ZnNi/NPC, this work provides an attractive solution to fabricate non-precious materials and offers a possible new strategy to replace Pt-based electrocatalysts for HER.

Fabrication of Te@NiTe2/NiS heterostructures for electrocatalytic hydrogen evolution reaction