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This article published in Chemical Communications discusses the enhancement of NiTiO3 piezocatalytic hydrogen evolution by doping it with large radius elements. The study found that when a metal element replaces the sites of nickel in NiTiO3, it results in lattice distortion and a higher piezoelectric response. Cd-doped NiTiO3 exhibited the highest H2 generation rate, which was 13 times that of the original NiTiO3. The research explores a new method to increase the piezocatalytic activity of materials and provides insights into the potential of ilmenite structure semiconductors in piezocatalysis. [Extracted from the article]

Efficient and cost-effective photocatalysts are pivotal for advancing large-scale solar hydrogen generation. Herein, we report a composite photocatalyst by incorporating MoS2 quantum dots (MoS2 QDs) as a cocatalyst into Cs3Bi2I9, resulting in a high enhancement in photocatalytic performance. Remarkably, the optimum MoS2 QDs/Cs3Bi2I9 composite achieves an impressive hydrogen evolution rate (6.09 mmol h−1 g−1) in an ethanol and HI/H3PO2 mixed solution. This rate is 8.8 times higher than pristine Cs3Bi2I9 (0.69 mmol h−1 g−1) and notably surpasses Pt/Cs3Bi2I9 (2.47 mmol h−1 g−1). Moreover, the composite displays exceptional stability during an 18-hour reaction, showcasing its potential for sustainable photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

Main-group elements are renowned for their versatile reactivities in organometallic chemistry, including CO2 insertion and H2 activation. However, electrocatalysts comprising a main-group element active site have not yet been widely developed for activating CO2 or producing H2. Recently, research has focused on main-group element-based electrocatalysts that are active in redox systems related to fuel-forming reactions. These studies have determined that the catalytic performances of heavier main-group element-based electrocatalysts are often similar to those of transition-metal-based electrocatalysts. Our group has recently reported the scope of including the main-group elements in the design of molecular catalysts and explored their applications in redox catalysis, such as the generation of H2 upon coupling of two protons (H+) and two electrons (e−). This feature article summarizes our research efforts in developing molecular electrocatalysts comprising main-group elements at their active sites. Furthermore, we highlight their influence on the rate-determining step, thereby enhancing the reaction rate and product selectivity for multi-H+/multi-e− transfer catalysis. Particularly, we focus on the performance of our recently reported molecular Sn- or Sb-centered macrocycles for electrocatalytic H2 evolution reaction (HER) and on how their mechanisms resemble those of transition-metal-based electrocatalysts. Moreover, we discuss the CO2 reduction reaction (CO2RR), another promising fuel-forming reaction, and emphasize the recent progress in including the main-group elements in the CO2RR. Although the main-group elements are found at the active sites of the molecular catalysts and are embedded in the electrode materials for studying the HER, molecular catalysts bearing main-group elements are not commonly used for CO2RR. However, the main-group elements assist the CO2RR by acting as co-catalysts. For example, alkali and alkaline earth metal ions (e.g., Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, and Ba2+) are known for their Lewis acidities, which influence the thermodynamic landscape of the CO2RR and product selectivity. In contrast, the elements in groups 13, 14, and 15 are primarily used as dopants in the preparation of catalytic materials. Overall, this article identifies main-group element-based molecular electrocatalysts and materials for HER and CO2RR. [ABSTRACT FROM AUTHOR]

Here, we report that the hydrogen evolution performance of a series of electrocatalysts with positive hydrogen adsorption energy ΔGH* (Ni2P, Ag, and Cu) can be enhanced by introducing LaNi5 as a cocatalyst. The enhancement is attributed to the synergy that LaNi5 enriches the adsorption of the hydrogen intermediate while the ΔGH* > 0 component provides active sites for hydrogen formation. [ABSTRACT FROM AUTHOR]

We report that the homogeneous light-driven hydrogen evolution reaction (HER) can be significantly enhanced by the presence of seemingly innocent ammonium (NH4+) cations. Experimental studies with different catalysts, photosensitizers and electron donors show this to be a general effect. Preliminary photophysical and mechanistic studies provide initial suggestions regarding the role of ammonium in the HER enhancement. [ABSTRACT FROM AUTHOR]

NiCl2·6H2O ([Ni(H2O)6]2Cl2) per se does not show electrocatalytic hydrogen evolution reaction activity (HER) in an acidic aqueous medium as well as in neutral water. Interestingly, when [Ni(H2O)6]2+ is present in a polyoxovanadate matrix, for example, in the compound K2[Ni(H2O)6]2[V10O28]·4H2O (1), it exhibits homogeneous electrocatalytic HER activity in an acidic aqueous solution with a turn over frequency of 2.1 s−1 and an effective low overpotential of 127 mV at pH 2.3. Compound 1 is the first nickel-containing polyoxometalate catalyst for hydrogen production via homogeneous electrocatalytic proton reduction without its decomposition under electrochemical conditions of HER. [ABSTRACT FROM AUTHOR]

We report that MoS2 nanosheets (MoS2 NSs) as a cocatalyst in situ coupled with MAPbI3 lead to a highly efficient composite photocatalyst for visible-light-driven photocatalytic H2 evolution. The most efficient MAPbI3/MoS2 NSs composite exhibits a high H2 evolution rate (206.1 μmol h−1) in MAPbI3-saturated HI solution, which is 121 times higher than that of pristine MAPbI3 (1.7 μmol h−1) and greatly superior to that of MAPbI3/Pt/C (68.5 μmol h−1), and the composite is very stable for H2 evolution in a 156 h reaction. [ABSTRACT FROM AUTHOR]

A self-assembled M6L8 type cage-connected 1D-coordination network of formula {[Ni6(MeSi(3py)3)8Cl9(H2O)2]Cl3·16H2O}∞ (1) was obtained from a 3-pyridyl substituted silane ligand MeSi(3py)3. This complex shows significantly high performance for the electrocatalytic and photocatalytic hydrogen evolution reaction (HER) in water. A maximum turnover number (TON) of 2824 has been observed for photocatalytic HER after 69 h. [ABSTRACT FROM AUTHOR]

An obvious H-UPD for a nano AuTiO2−x composite has been found for the first time in terms of the electrochemical characteristics of the Au composite. The electronic effect between Au and TiO2 and the oxygen vacancy defect would change the adsorption energy of H and HER activity. The HER activity of the AuTiO2−x electrode is 6.44 times that of the Au electrode. [ABSTRACT FROM AUTHOR]

We demonstrate a lamellar NiMoCo@CuS catalyst, showing not only an excellent catalyst performance (η100@72 mV and a Tafel slope of 47 mV dec−1), but also a good stability (20 mA cm−2@30 hours), outperforming the NiMo system and noble Pt. [ABSTRACT FROM AUTHOR]

Herein, we report that vanadium carbide (VC) can efficiently catalyze photocatalytic H2 evolution with excellent stability in a dye-sensitized system under visible light irradiation (≥420 nm) and also serve as an versatile H2 evolution cocatalyst when integrated with various semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

Herein, a Mn3O4 nanooctahedron (NO) supported Pd nanocomposite has been fabricated from a chosen thermodynamically allowed redox transformation reaction. The synthesized Pd–Mn3O4 (PMO) nanocomposite exhibits outstanding electrocatalytic activity for the hydrogen evolution reaction (HER) in acidic medium with a low overpotential (14 mV), small Tafel slope (42 mV dec−1) and high exchange current density (7.74 mA cm−2). Moreover, the exceptional durability displayed by PMO on conducting 5000 CV cycles as well as its long-term stability for 36 h (97% activity retention) deserve special attention. [ABSTRACT FROM AUTHOR]