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Benefiting from ordered atomic structures and strong d‐orbital interactions, intermetallic compounds (IMCs) are promising electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, the body‐centered cubic IrGa IMCs with atomic donor–acceptor architectures are synthesized and anchored on the nitrogen‐doped reduced graphene oxide (i.e., IrGa/N‐rGO). Structural characterizations and theoretical calculations reveal that the electron‐rich Ir sites are atomically dispersed in IrGa/N‐rGO, facilitating the electron transfer between Ir atoms and adsorbed species, which can efficiently decrease the energy barriers of the potential determining step for both HER and OER. Impressively, the IrGa/N‐rGO||IrGa/N‐rGO exhibits excellent performance for overall water splitting in alkaline medium, requiring a low cell voltage of 1.51 V to achieve 10 mA cm−2, meanwhile, exhibiting no significant degradation for 100 h. This work demonstrates that the rational design of noble metal electrocatalysts with donor–acceptor architectures is beneficial for catalytic reactions in energy conversion applications. [ABSTRACT FROM AUTHOR]

Constructing amorphous/intermetallic (A/IMC) heterophase structures by breaking the highly ordered IMC phase with disordered amorphous phase is an effective way to improve the electrocatalytic performance of noble metal‐based IMC electrocatalysts because of the optimized electronic structure and abundant heterophase boundaries as active sites. In this study, we report the synthesis of ultrathin A/IMC PtPbBi nanosheets (NSs) for boosting hydrogen evolution reaction (HER) and alcohol oxidation reactions. The resulting A/IMC PtPbBi NSs exhibit a remarkably low overpotential of only 25 mV at 10 mA cm−2 for the HER in an acidic electrolyte, together with outstanding stability for 100 h. In addition, the PtPbBi NSs show high mass activities for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR), which are 13.2 and 14.5 times higher than those of commercial Pt/C, respectively. Density functional theory calculations demonstrate that the synergistic effect of amorphous/intermetallic components and multimetallic composition facilitate the electron transfer from the catalyst to key intermediates, thus improving the catalytic activity of MOR. This work establishes a novel pathway for the synthesis of heterophase two‐dimensional nanomaterials with high electrocatalytic performance across a wide range of electrochemical applications. [ABSTRACT FROM AUTHOR]

Constructing amorphous/intermetallic (A/IMC) heterophase structures by breaking the highly ordered IMC phase with disordered amorphous phase is an effective way to improve the electrocatalytic performance of noble metal‐based IMC electrocatalysts because of the optimized electronic structure and abundant heterophase boundaries as active sites. In this study, we report the synthesis of ultrathin A/IMC PtPbBi nanosheets (NSs) for boosting hydrogen evolution reaction (HER) and alcohol oxidation reactions. The resulting A/IMC PtPbBi NSs exhibit a remarkably low overpotential of only 25 mV at 10 mA cm−2 for the HER in an acidic electrolyte, together with outstanding stability for 100 h. In addition, the PtPbBi NSs show high mass activities for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR), which are 13.2 and 14.5 times higher than those of commercial Pt/C, respectively. Density functional theory calculations demonstrate that the synergistic effect of amorphous/intermetallic components and multimetallic composition facilitate the electron transfer from the catalyst to key intermediates, thus improving the catalytic activity of MOR. This work establishes a novel pathway for the synthesis of heterophase two‐dimensional nanomaterials with high electrocatalytic performance across a wide range of electrochemical applications. [ABSTRACT FROM AUTHOR]

The Sc 2 CCl 2 /WSe 2 and Sc 2 CCl 2 /WTe 2 heterostructures are identified for efficient photocatalytic overall water splitting with direct Z-schemes, although the conduct band minimum for the Sc 2 CCl 2 monolayer and the valence band maximums of the WSe 2 and WTe 2 ones do not match the redox potential conditions. The photocatalytic direct Z-schemes are constructed for the two heterostructures according to the built-in electric fields and band alignments. The solar-to-hydrogen efficiency η S T H , together with the Gibbs free energies are evaluated to understand the photocatalytic activities and feasibilities. The maximum η S T H can reach 20.70% with the Sc 2 CCl 2 /WTe 2 heterostructure and higher than 7.35% with the Sc 2 CCl 2 /WSe 2 one. Interestingly, the biaxial tensile strains remarkably boost the η S T H of the Sc 2 CCl 2 /WSe 2 heterostructure but weakly impact that of the Sc 2 CCl 2 /WTe 2 one, while the compressive strains substantially reduce the η S T H of the Sc 2 CCl 2 /WSe 2 heterostructure but raise that of the Sc 2 CCl 2 /WTe 2 one. Moreover, the Gibbs free energies indicate the considered hydrogen and oxygen evolution reactions have thermodynamic feasibilities. [Display omitted] • Sc 2 CCl 2 /WX 2 (X = Se, Te) heterostructures can drive overall water splitting. • Solar-to-hydrogen efficiencies of Sc 2 CCl 2 /WTe 2 and Sc 2 CCl 2 /WSe 2 can reach 20.70% 7.35%. • Biaxial strains impact the η STH s of the Sc 2 CCl 2 /WX 2 (X = Se, Te) heterostructures remarkably. • Thermodynamic feasibilities of HER and OER are confirmed by the Gibbs free energies. [ABSTRACT FROM AUTHOR]

The photocatalytic direct Z-scheme driven by two-dimensional (2D) heterostructure often achieve high solar-to-hydrogen conversion efficiency (η STH). However, the favorable 2D heterostructure is not easily identified. Here, we identify a 2D heterostructure with InTe and Bismuthene monolayers and confirm the most stable configurations. The band alignments and built-in electric fields both turn out to satisfy the requirement of the direct Z-scheme for hydrogen evolution reaction. In addition, the optical absorption, mobility, η STH and the change in Gibbs free energy is used to justify the photocatalytic performance. The maximum η STH can reach 9.67% which is significantly higher than 4.22% of the InTe monolayer. Moreover, the η STH of the heterostructure can be raised to 16.17% under +9% biaxial strains, indicating that strains have a controlling effect on the η STH s. The alterations in Gibbs free energies of 1.72–2.12 eV assure the hydrogen evolution reactions are feasible in thermodynamics. Therefore, the present InTe/Bismuthene heterostructure has potential applications in driving photocatalytic hydrogen generation from overall water splitting under the irradiation of sunlight. [Display omitted] • InTe/Bismuthene heterostructure can drive hydrogen generation from water splitting. • The maximum solar-to-hydrogen efficiency can reach 16.17% under +9% strains. • InTe/Bismuthene heterojunction raises efficiency compared to the InTe monolayer. • The thermodynamic feasibility of the HERs is confirmed with Gibbs free energy changes. [ABSTRACT FROM AUTHOR]

Two nanoribbon heterostructures are suitable for driving efficient direct Z-schemes of the photocatalytic overall water splitting for hydrogen production and are screened out of nine heterostructures constructed from edge-passivated antimonene (SbNR-X) and arsenide (AsNR-X, X = F, Cl, CN) nanoribbons. The solar-to-hydrogen (STH) efficiency and the Gibbs free energies (ΔGs) of the redox reactions at different sites are calculated to identify the preferable Z-schemes. Meanwhile, the transfer and recombination of the photogenerated carriers are explored by using nonadiabatic molecular dynamics (NAMD) simulations. The obtained band alignments and built-in electric fields of the two considered heterostructures can match the requirements of the photocatalytic Z-scheme, and the corresponding STH efficiencies can reach 15.04 % and 30.53 %, respectively. The oxidation evolution reactions can proceed spontaneously, and hydrogen evolution reactions are feasible in thermodynamics. NAMD simulations show that the SbNR-CN/AsNR-CN nanoribbon heterostructure has faster interlayer recombination but slower transfer of the photogenerated electron from the SbNR-CN to AsNR-CN nanoribbons and of the photogenerated hole along the reversible direction, indicating that this heterostructure has a higher carrier utilization rate. These findings confirm that the SbNR-CN/AsNR-CN nanoribbon heterostructure is a promising candidate for developing high STH efficiency materials with direct Z-schemes. [Display omitted] • Photocatalytic Z-schemes are built for antimonene/arsenide nanoribbon heterostructures. • STH efficiencies of 15.04 % and 30.53 % are achieved by the constructed schemes. • OER can procced spontaneously with dual-site process and HER is feasible in thermodynamics. • Transfer and recombination of carriers are elucidated by nonadiabatic dynamics simulations. [ABSTRACT FROM AUTHOR]

Catalysts based on Cu nanocrystals (NCs) for electrochemical CO2‐to‐C2+ conversion with high activity have been a subject of considerable interest, but poor stability and low selectivity for a single C2+ product remain obstacles for realizing sustainable carbon‐neutral cycles. Here, we used the facet‐selective atomic layer deposition (FS‐ALD) technique to selectively cover the (111) surface of Cu NCs with ultrathin Al2O3 to increase the exposed facet ratio of (100)/(111), resulting in a faradaic efficiency ratio of C2H4/CH4 for overcoated Cu NCs 22 times higher than that for pure Cu NCs. Peak performance of the overcoated catalyst (Cu NCs/Al2O3‐10C) reaches a C2H4 faradaic efficiency of 60.4 % at a current density of 300 mA cm−2 in 5 M KOH electrolyte, when using a gas diffusion electrode flow cell. Moreover, the Al2O3 overcoating effectively suppresses the dynamic mobility and the aggregation of Cu NCs, which explains the negligible activity loss and selectivity degradations of Cu NCs/Al2O3‐10C shown in stability tests. [ABSTRACT FROM AUTHOR]

Catalysts based on Cu nanocrystals (NCs) for electrochemical CO2‐to‐C2+ conversion with high activity have been a subject of considerable interest, but poor stability and low selectivity for a single C2+ product remain obstacles for realizing sustainable carbon‐neutral cycles. Here, we used the facet‐selective atomic layer deposition (FS‐ALD) technique to selectively cover the (111) surface of Cu NCs with ultrathin Al2O3 to increase the exposed facet ratio of (100)/(111), resulting in a faradaic efficiency ratio of C2H4/CH4 for overcoated Cu NCs 22 times higher than that for pure Cu NCs. Peak performance of the overcoated catalyst (Cu NCs/Al2O3‐10C) reaches a C2H4 faradaic efficiency of 60.4 % at a current density of 300 mA cm−2 in 5 M KOH electrolyte, when using a gas diffusion electrode flow cell. Moreover, the Al2O3 overcoating effectively suppresses the dynamic mobility and the aggregation of Cu NCs, which explains the negligible activity loss and selectivity degradations of Cu NCs/Al2O3‐10C shown in stability tests. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoNi 2 S 4 nanoparticles with high mass loading (15 mg cm−2) grown on carbon cloth. • High capacitance of 10.87F cm−2 at 10 mA cm−2 and a prominent coulombic efficiency. • All-solid-state hybrid supercapacitor delivers 1.42 mWh cm−2 at 9.0 mW cm−2. • Excellent HER (84 mV at 10 mA cm−2) and OER (228 mV at 10 mA cm−2) activities. Transition-metal sulfides are regarded as one of the most potential materials for the supercapacitor and electrocatalyst, and the holey alignments of the active materials with effective availability is highly required due to the rich active sites and convenient electrolyte access for surface reaction. Herein, we report the growth of CoNi 2 S 4 nanoparticles with high mass loading (14.8 mg cm−2) on the surface of carbon cloth (CC) by a two-step hydrothermal sulfuration. The CoNi 2 S 4 /CC electrode has the holey characteristic containing rich active sites for electrolyte access, and shows a high areal capacitance of 10.87 C cm−2 at 10 mA cm−2 and a prominent coulombic efficiency. Furthermore, the as-assembled hybrid supercapacitor delivers a high areal capacitance of 3.16 F cm−2, an energy density of 1.42 mWh cm−2 at a power density of 9.0 mW cm−2, and a high capacitance retention of 92.5% after 20,000 cycles. As an electrocatalyst, CoNi 2 S 4 /CC electrode possesses an excellent hydrogen evolution reaction (overpotential of 84 mV at 10 mA cm−2) and oxygen evolution reaction (228 mV at 10 mA cm−2) activities in 1.0 M KOH solution. Moreover, the overall water splitting electrolyzer assembled by CoNi 2 S 4 /CC exhibits a low cell voltage (1.51 V@10 mA cm−2) and a high durability. [ABSTRACT FROM AUTHOR]

[Display omitted] • 7 Ga 2 S 3 monolayers for photocatalytic hydrogen generation are screened from 1038 ones. • The maximum solar-to-hydrogen efficiency of 17.71% can be achieved. • Several new Ga 2 S 3 monolayers with efficiency superior to the reported one are found. • Feasibilities of hydrogen evolution reactions are confirmed by the Gibbs free energy. • Stabilities of the monolayers are ensured by phonon dispersions and AIMD simulations. Screening unique structures are critical to developing efficient photocatalytic materials for solar-to-hydrogen conversion via hydrogen evolution reaction (HER). Here, we demonstrate the discovery of two-dimensional Ga 2 S 3 monolayers as efficient photocatalysts. By performing screening over 30 generations of 30 populations using the universal structure predictor evolutionary xtallography method, accompanied by accessing the stabilities and matching with photocatalytic conditions for overall water splitting, we identify 7 preferable configurations from 1038 Ga 2 S 3 monolayers. The bandgaps and overpotentials of the band edges of these monolayers are used to justify the hydrogen and oxygen evolution reactions and evaluate the solar-to-hydrogen conversion efficiencies, and alterations of Gibbs free energy in HERs and oxygen evolution reactions (OERs) are calculated to validate the thermodynamics feasibility. The maximum efficiency of 17.71% is observed for one Ga 2 S 3 monolayer with the P1 space group, and higher efficiency of 19.58% can be boosted with a suitable strain. Moreover, the moderate alterations of the Gibbs free energy assure the HERs are achievable in thermodynamics and the OERs can proceed spontaneously in thermodynamics on the GS-1, 4, 6, and 7 monolayers, although those on the GS-2, 3, 5 monolayers need small external energies. These results indicate that the screened Ga 2 S 3 monolayers can be used as promising candidates for sunlight photocatalytic overall water splitting to manufacture hydrogen. [ABSTRACT FROM AUTHOR]

[Display omitted] • The maximum η ' S T H of heterostructures reach 31.17% under 4% biaxial tensile strain. • The η ' S T H can boost to 19.88% for heterostructures comprising the doped monolayers. • The η ' S T H can increase to 12.50% with the Se-doped monolayer of AgInP 2 S 3 Se 3. • STH efficiency η ' S T H of 6.41% can be achieved for the AgInP 2 S 6 monolayer. To achieve high solar-to-hydrogen efficiency ( η ' S T H ), we identify the geometrical structures of seven heterostructures comprising the pristine and doped AgInP 2 S 6 monolayers and confirm the stabilities. The electronic properties by HSE06 with dipole corrections are used to demonstrate the charge polarization and the built-in electric field in heterostructure. The direct Z-schemes for hydrogen evolution on the heterostructures are constructed based on the projected band edge potentials of each monolayer, and the corresponding s are evaluated. The results demonstrate that both doping and constructing heterostructure can significantly boost the s. Remarkably, the Se-doped AgInP 2 S 6 monolayer promotes the from 6.41% to 12.50%, while the two configurations of the AgInP 2 S 3 Se 3 /AgInP 2 S 3 Te 3 heterostructure raise to 17.59% and 19.88%, respectively. The corresponding total energy conversion efficiency reach 0.37% and 0.43%. Moreover, strain engineering significantly impacts with either boosting or degrading effects depending on the different strains. The highest of 31.17% can be achieved for the AgInP 2 S 3 Se 3 /AgInP 2 S 3 Te 3 heterostructure under 4% biaxial tensile strain. The changes of −0.15–1.69 eV for the Gibbs free energies in the hydrogen evolution reactions indicate these reactions are feasible in thermodynamics. Therefore, the heterostructures based on the Se/Te doped AgInP 2 S 6 monolayers, especially the AgInP 2 S 3 Se 3 /AgInP 2 S 3 Te 3 one, are a potential candidate for developing high efficient photocatalysts. [ABSTRACT FROM AUTHOR]

We identify two configurations of the HfSe 2 /InSe van der Waals heterostructure that can drive photocatalytic overall water splitting reactions with high solar-to-hydrogen (STH) efficiency after investigating four different configurations (represented by HI, HIx, HIy, and HyI) for the heterostructure. The electronic properties, optical absorption, and mobility are calculated by using the obtained structures. The projected band edges and the interfacial built-in electric fields for the two monolayers demonstrate that the two configurations are type-II heterostructures that can match the conditions for photocatalytic hydrogen generation from water splitting, while the other two configurations have no satisfactory band edge for the overall water splitting. The corrected STH efficiency (η ′ STH) is calculated based on the obtained overpotentials and bandgaps, which give 25.24% and 25.07% for the two configurations, respectively. The effects of strain engineering on η ′ STH are also investigated but turn out to be not significant. In addition, the Gibbs free energy changes (Δ G s) are calculated to confirm the thermodynamic feasibilities of the hydrogen/oxygen evolution reactions. The obtained Δ G s in the redox reaction for the two configurations indicate that the hydrogen/oxygen evolution reactions are feasible from the view of thermodynamics. Apparently, the HfSe 2 /InSe heterostructure is a potential candidate for developing high STH efficiency photocatalysts. [Display omitted] • HfSe 2 /InSe heterostructure is identified for photocatalytic overall water splitting. • The maximum solar-to-hydrogen efficiency of the heterostructure can reach 25.24%. • The solar-to-hydrogen efficiency is raised by −1% strain but reduced by other ones. • The Gibbs free energy changes support the feasibility of HER/OER. [ABSTRACT FROM AUTHOR]

The solar photocatalytic hydrogen evolution reaction (HER) with Z-scheme driven by the two-dimensional (2D) AuSe/SnSe heterostructure is explored. Three preferable geometrical configurations of the heterostructure are identified from nine structures stacked with the SnSe and AuSe monolayers by formation energies, and thermodynamic stability is confirmed by ab initio molecular dynamics simulation at 400 K. The projected band edges of the monolayers in the heterostructure, interlayer charge transfer, and built-in fields support the AuSe/SnSe heterostructure to drive the photocatalytic HER with the direct Z-scheme, which increases not only the overpotentials of the photocatalytic water decomposition to produce hydrogen, but also the optical absorptions. Thus, the maximum solar-to-hydrogen conversion efficiency could attain 32.95% if a suitable biaxial strain is applied. The effects of the interlayer distance on the geometrical structures and electronic properties are also examined, and the results show that the increase in distance is safe, but the decrease will damage the character of the vdW heterostructure. The changes of Gibbs free energies confirm that the HER with Z-scheme driven by the AuSe/SnSe heterostructure is feasible. These results could provide a theoretical guide for the development of photocatalysts for the efficient HER with the direct Z-scheme by using the AuSe/SnSe heterostructure. [Display omitted] • The stable configurations of the AuSe/SnSe heterostructure are identified. • The newfound heterostructure can drive solar photocatalytic HER with Z-scheme. • 32.95% of solar-to-hydrogen conversion efficiency can be achieved under 4% strain. • Both strain and interlayer distance impact the band edges and conversion efficiency. • The feasibility of the HER with Z-scheme is confirmed with Gibbs free energy changes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The XBiSe 3 (X = Ga, In, Tl) monolayers are predicted and stabilities are confirmed. • InBiSe 3 monolayer can meet the conditions of HER under strains heavier than −3%. • The high electron mobility is identified for the TiBiSe 3 monolayer. • The enhanced optical absorption in the visible light and UV regions are observed. • The band alignment and optical absorption can be controlled effectively by strain. The geometrical configurations of the XBiSe 3 (X = Ga, In, Tl) monolayers are identified by employing the first-principles density functional theory calculations, and the stabilities are confirmed by phonon dispersion, formation energy, and ab initio molecular dynamics simulation, respectively. The bandgap and band edges, the density of states, the optical absorption, mobility, and effect of strain engineering are evaluated to understand the photoelectronic properties of the monolayers. The results show that the XBiSe 3 monolayers have the indirect bandgaps of 1.14–1.69 (1.20–1.84) eV by HSE06(GW), leading to the enhanced optical absorption from the visible to near-ultraviolet region. The large mobility of the electron and hole are also observed, which is helpful for the separation and transfer of the photogenerated carrier pair. The band edges and bandgaps, as well as the optical absorptions, can effectively be tuned by strain engineering. It should be noted that the band edges of the InBiSe 3 monolayer could satisfy the condition of redox potential for the hydrogen evolution reaction under the compressive strain heavier than −3%, implicating this monolayer can also be used for photocatalytic water splitting to produce hydrogen. Therefore, these monolayers have potential applications in photocatalytic materials or photoelectronic devices such as energy harvesters and visible-light sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The SiMI 4 (M = Ge, Sn) monolayer is a promising candidate for photocatalytic HER. • The geometrical structure of the SiMI 4 (M = Ge, Sn) monolayer is predicted. • Dynamical and thermal stabilities are confirmed by phonon dispersion and AIMD. • Band edges and absorptions of SiMI 4 monolayers can be effectively tuned with strain. • Gibbs energy of HER and direct splitting of the H 2 O molecule are investigated. Two-dimensional (2D) materials of SiMI 4 (M = Ge, Sn) monolayers are identified as promising visible-light-driven photocatalyst for hydrogen evolution reaction by DFT calculations. The dynamical and thermal stabilities of the two monolayers are confirmed by the phonon dispersion calculations and ab initio molecular dynamics (AIMD) simulations, respectively. The results show that the two 2D materials have indirect bandgaps of 2.45 and 2.43 eV, and the band edges can match the hydrogen evolution reaction conditions. Absorption spectra show that the monolayers respond to visible light and can be tuned by different strains. Besides, the hole and electron mobilities are different, which is beneficial for photoelectronic performance. The mechanisms of the hydrogen evolution reaction and the direct water splitting process are also explored. The calculational results support the promising applications of SiMI 4 (M = Ge, Sn) monolayers as visible-light-driven photocatalyst of hydrogen production. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three new Bi 2 Se 3 monolayers are predicted, and their stabilities are confirmed. • The newfound monolayers can match the conditions of HER + OER with or without strain. • The enhanced optical absorption in the visible-light and UV regions are observed. • The band alignment and optical absorption can be controlled effectively by strain. Considering the reported Bi 2 Se 3 monolayer with P-3 M1 space group cannot match energy band edges for the hydrogen evolution reaction(HER) and the oxygen evolution reaction(OER), we identify three Bi 2 Se 3 monolayers with desirable bandgap, band edges, and optical absorption for the redox reactions, based on the twenty two-dimensional structures screened by using Universal Structure Predictor: Evolutionary Xtallography with the first-principles calculations. The stabilities of the identified geometrical configurations are confirmed by phonon dispersion and ab initio molecular dynamics simulation, respectively. The density of states, bandgap and band edges, the optical absorption, mobility, and effect of strain engineering are determined and used to evaluate the photoelectronic properties of the monolayers. The results show that the I-Bi 2 Se 3 monolayer possesses an approximate direct bandgap of 1.44/1.77 eV by HSE06/GW. However, the II-Bi 2 Se 3 and III-Bi 2 Se 3 monolayers show indirect bandgaps of 1.91 and 2.15 eV by HSE06 and 1.99 and 2.84 eV by GW. The band edges can match the redox potentials of HER and OER, although one of them needs + 3% biaxial tensile strain. The enhanced visible-light and UV absorptions and apparent mobility difference between the electron and hole are also observed. All results support the newfound Bi 2 Se 3 monolayers could be candidates for HER and OER. [ABSTRACT FROM AUTHOR]