ABSTRACT The development of efficient molecular cobalt electrocatalysts for the hydrogen evolution reaction (HER) is of considerable interest for sustainable hydrogen production. Herein, three heteroleptic Co(II) complexes, [Co( L (OMe) )bpyCl]ClO 4 ( 1 ), [Co( L (OMe) )dmbpyCl]ClO 4 ( 2 ), and [Co( L (OMe) )phenCl]ClO 4 ( 3 ) ( L = 2‐chloro‐4,6‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐1,3,5‐triazine), were synthesized and comprehensively characterized, including single‐crystal X‐ray diffraction (SCXRD), which confirmed distorted octahedral geometries around the Co(II) center for all. Their electrocatalytic HER activity was investigated in anhydrous acetonitrile using acetic acid as the proton source. All complexes exhibited pronounced catalytic current enhancement in the ligand‐centered reduction region, affording HER overpotentials of 0.53–0.61 V. Controlled‐potential electrolysis confirmed hydrogen evolution with faradaic efficiencies of 92.5%, 98.4%, and 74.4% for complexes 1 , 2 and 3 , respectively. Post‐catalytic rinse tests, UV–vis spectroscopy, electrochemical stability studies, and field‐emission scanning electron microscopy/energy‐dispersive x‐ray spectroscopy (FE‐SEM/EDS) analyses confirmed the homogeneous nature of the catalysts. Combined electrochemical and theoretical investigations indicate ligand‐centered reduction prior to the cobalt hydride formation. Complex 2 exhibited the highest TOF and Faradaic efficiency under the AcOH electrolysis conditions, highlighting the role of ancillary‐ligand electronic modulation in tuning the redox properties and HER activity, establishing a clear structure–activity relationship for the rational design of efficient cobalt‐based molecular HER electrocatalysts.
ABSTRACT 1,4‐Butanediol (BDO) and γ‐butyrolactone (GBL) are multifunctional intermediate chemicals and have been used in a variety of valuable chemical products. This review presents a comprehensive analysis of the industrial importance, production methods, and economic considerations of BDO and GBL. The industrial landscape of BDO and GBL is examined through major commercial processes, key patents, and industrial players, highlighting their expanding role in the production of value‐added chemicals. Among the available GBL production routes, a laboratory approach of vapor‐phase dehydrogenation of BDO over copper‐based catalysts has attracted considerable attention because of its potential for efficient, and scalable GBL production. Furthermore, this review evaluates the influence of copper‐based catalyst composition, and metal‐support interactions on overall catalytic activity. Besides the fundamental catalyst development, the review highlights main issues of catalyst deactivation, process efficiency, and scale‐up limitations in industrial implementation. Additionally, the link between catalyst properties and reaction conditions is highlighted to guide the development and optimisation of robust catalytic systems. In addition to the fundamental and technological analysis of catalytic conversion of BDO to GBL, current market trends, demands and production capacity of BDO and GBL are assessed to reveal their impact on the global BDO and GBL market.
ABSTRACT 1,5‐Pentanediol (1,5‐PeD), a valuable platform chemical derived from furfural (FA), holds a pivotal role in the industrial production of polymers. However, converting FA to high‐value 1,5‐PeD via hydrogenolysis with non‐precious metal catalysts is a promising yet challenging approach. In this study, CuCo/MgO catalysts were synthesized via coprecipitation, with the 2Cu38Co/MgO catalyst showing superior catalytic efficiency, achieving a 1,5‐PeD yield of 42.2%. Introducing Cu alters the extent to which Co species are reduced, resulting in more Co 2+ ‐oxygen vacancy (O v )pairs. Synergistic catalysis among different active sites is crucial for the effective functioning of catalysts. Extensive characterization analysis results reveal that Cu 0 and Co 2+ ‐O v pairs have synergistic catalytic effects. Dissociation of hydrogen occurs on Cu nanoparticles, rapidly hydrogenating FA adsorbs on MgO to furfuryl alcohol (FOL), and the dissociated FOL adsorbs on the Co 2+ ‐O v pairs, opening the ring to generate 1,5‐PeD. The study provides novel insights into the development of non‐noble metal catalysts to upgrade biomass‐derived FA to 1,5‐PeD.
ABSTRACT The methanation of CO 2 represents a promising strategy for carbon capture utilization and renewable energy storage, yet developing catalysts that combine high low‐temperature activity, selectivity, and stability remains a significant challenge. Here, we report a cobalt‐promoted thermally stable NiAl 2 O 4 (NAO) catalyst (5%Co/NAO) that addresses these limitations. The incorporation of Co induces profound changes in both the electronic structure and the reaction mechanism. The electronic modulation enhances metal‐support and metal‐metal interactions, promoting the formation of small Ni nanoparticles and oxygen vacancies. Critically, in situ DRIFTS demonstrates that the addition of Co switches the reaction pathway from a single associative (formate) route on pristine NAO to a dual associative‐dissociative pathway on 5%Co/NAO, involving both formate (HCOO*) and CO* intermediates. The presence of the CO* pathway accelerates low‐temperature CO 2 activation and the rate‐limiting hydrogenation of HCOO* to CHO*. Consequently, 5%Co/NAO achieves 18% CO 2 conversion at 220°C and 89% at 300°C, with a lower apparent activation energy (81.20 kJ mol −1 ) and a CH 4 selectivity of ∼93%. The catalyst also exhibits outstanding stability without sintering or coking during 100 h tests. This work establishes that Co‐Ni synergy and enabling a dual reaction pathway, offers a powerful design strategy for efficient low‐temperature CO 2 methanation catalysts.
ABSTRACT The PN acetate ruthenium(II) complex [Ru(κ 2 ‐OAc)(PPye) 2 ]OAc ( 1 ) was synthesized from [Ru(κ 2 ‐OAc) 2 (PPh 3 ) 2 ] and 1‐(diphenylphosphino)‐2‐(2‐pyridyl)ethane (PPye) in methanol and isolated in 70% yield. Treatment of [Ru(κ 2 ‐OAc) 2 (PPh 3 ) 2 ] with 2‐(diphenylphosphino)pyridine (PPy) afforded [Ru(κ 1 OAc)(PPh 3 )(PPy) 2 ]OAc ( 2 ) in high yield. The complexes 1 and 2 display photocatalytic activity in the TH of ketones using 2‐propanol. Complex 1 exhibits superior activity, affording quantitative conversion of aryl ketones under mild conditions (40°C), whereas no activity was observed in dark. On–off experiments confirmed a photoresponsive nature of the catalytic process. Mechanistic studies revealed the formation of different ruthenium monohydride species under thermal and irradiated conditions. Luminescence quenching studies in the presence of NaO i Pr support the involvement of excited‐state processes associated with alkoxide activation and hydride generation.
