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Magnesium hydride (MgH2) has been considered as a promising hydrogen storage material for buildings that are powered by hydrogen energy, but its practical application is hampered by poor kinetics and unstable thermodynamics. Herein, we describe a feasible method for preparing FeNi nanoparticles dispersed on reduced graphene oxide nanosheets (FeNi/rGO), and we confirmed that excellent catalytic effects increased the hydrogen storage performance of MgH2. 5 wt% FeNi/rGO-modified MgH2 began to release hydrogen at 230 °C and liberated 6.5 wt% H2 within 10 min at 300 °C. As for the hydrogenation process, the dehydrogenated sample absorbed 5.4 wt% H2 within 20 min at 125 °C under a hydrogen pressure of 32 bar. More importantly, a hydrogen capacity of 6.9 wt% was maintained after 50 cycles without compromising the kinetics during each cycle. A unique catalytic mechanism promoted synergetic effects between the in situ-formed Mg2Ni/Mg2NiH4, Fe, and rGO that efficiently promoted hydrogen dissociation and diffusion along the Mg/MgH2 interface, anchored the catalyst, and prevented MgH2 from aggregation and growth.

Reversible hydrogen storage in MgH2 under mild conditions is a promising way for the realization of “Hydrogen Economy”, in which the development of cheap and highly efficient catalysts is the major challenge. Herein, A two-dimensional layered Fe is prepared via a facile wet-chemical ball milling method and has been confirmed to greatly enhance the hydrogen storage performance of MgH2. Minor addition of 5 wt% Fe nanosheets to MgH2 decreases the onset desorption temperature to 182.1 °C and enables a quick release of 5.44 wt% H2 within 10 min at 300 °C. Besides, the dehydrogenated sample takes up 6 wt% H2 in 10 min under a hydrogen pressure of 3.2 MPa at 200 °C. With the doping of Fe nanosheets, the apparent activation energy of the dehydrogenation reaction for MgH2 is reduced to 40.7 ± 1.0 kJ mol−1. Further ab initio calculations reveal that the presence of Fe extends the Mg–H bond length and reduces its bond strength. We believe that this work would shed light on designing plain metal for catalysis in the area of hydrogen storage and other energy-related issues.

Carbon materials play an important role in the development of solid hydrogen storage materials. The main purpose of this work is to study the low-cost synthesis of biomass carbon (BC) and its positive effect on the hydrogen storage behavior of magnesium hydride (MgH2). Herein, it is proven that when biomass carbon (BC) is used together with magnesium hydride (MgH2), biomass carbon can be used as an adsorption and desorption channel for hydrogen. The initial dehydrogenation temperature of MgH2 + 10 wt% BC composite is 250 °C, which is 110 °C lower than that of pure MgH2. In addition, the MgH2 + 10 wt% BC composite system can complete all dehydrogenation processes within 10 min at 350 °C. Meanwhile, 5.1 wt% H2 can also be dehydrogenated within 1 h at 300 °C. Under the same conditions, MgH2 hardly starts to release hydrogen. After complete dehydrogenation, the composite can start to absorb hydrogen at 110 °C. Under the conditions of 225 °C and 3 MPa, 6.13 wt% H2 can be absorbed within 1 h, basically reaching the theoretical dehydrogenation limit. Cycling experiments show that the MgH2 + 10 wt% BC composite has a good stability. After 10 cycles, the hydrogen storage capacity shows almost no obvious decline. It is believed that this study can help in the research and development of efficient carbon-based multifunctional catalysts.

Magnesium hydride (MgH2) is considered as a promising hydrogen storage material for “hydrogen economy” due to its high capacity; however, its stable thermodynamics and slow kinetics hinder its practical applications. Transition metal catalysts attract intense interest in modifying MgH2 systems. Herein, FeCo nanosheets with a thickness of 50 nm were successfully prepared and confirmed to have superior catalytic effects on MgH2. The nano-FeCo-catalyzed MgH2 started to release hydrogen at 200 °C which ended at 320 °C, while the hydrogen desorption process of pure MgH2 occurred at 350–420 °C. Besides, the dehydrogenated FeCo-containing sample could rapidly take up 6.7 wt% H2 within 1 min at 300 °C. Furthermore, after doping with nano-FeCo, the activation energy of hydrogen desorption and absorption was dramatically reduced to 65.3 ± 4.7 kJ mol−1 and 53.4 ± 1.0 kJ mol−1, respectively. In a word, our findings may provide references for designing and producing nano-level intermetallic catalysts for the research area of hydrogen storage or other energy-related research.

At present, catalyst doping has been widely concerned by researchers as an effective method to improve the hydrogen storage performance of MgH2. Herein, it is confirmed that MnMoO4 rod catalyst can effectively improve the hydrogen storage performance of MgH2. According to the experimental results, MgH2+10 wt%MnMoO4 composite material starts dehydrogenation at about 220 °C, which is about 140 °C lower than MgH2 without additives. The initial dehydrogenation capacity of 6 wt% can be reached within 10min at 300 °C. After complete dehydrogenation, H2 can be absorbed below 55 °C, and 4.34 wt% H2 can be absorbed within 15 min at 150 °C and 3 MPa hydrogen pressure. In addition, the activation energy of dehydrogenation of MgH2 decreased about 45 kJ mol−1. Furthermore, hydrogen storage capacity of MgH2 can still be maintained at 5.85 wt% after 20 cycles. The synergy between the in-situ formed Mn and MgMo2O7 may help promote the dissociation and diffusion of H2 along the Mg/MgH2 interface, thereby improving the hydrogen storage performance of MgH2.

A novel approach toward quaternary carbon centered cyclobutanes through Pd(II)-catalyzed sequential intramolecular methylene C–H alkylation and intermolecular methine C–H bond arylation, alkenylation, alkylation, alkynylation, allylation, benzylation or alkoxylation is described. These quaternary carbon centered cyclobutanes could be further diversified through Pd(II)-catalyzed γ-C(sp3)–H bond activations. The synthetic utility of this novel approach was exemplified by its application to the synthesis of a bioactive small molecule.

Primary mechanism of a PdII -catalyzed 8-aminoquinoline-directed C-H alkoxylation was investigated. It was understood that the PdII -catalyzed C(sp3 )-O bond formation proceeded through a concerted reductive elimination from the PdIV intermediate in the cyclic system. Deuteration experiments and related computational studies elucidate that intrinsic conformation determined the diastereoselectivity of the PdII -catalyzed C-H alkoxylation of cyclic carboxylic acids.

In recent years, transition metal-catalyzed C(sp3)H functionalization has gradually emerged as a practical and powerful tool to prepare highly valuable chemicals. In this mini-review, we will give some examples to cover recent research advances on transition-metal (Pd, Ni) catalyzed C(sp3)H functionalization via bidentate directing group coordination. Different bidentate directing groups will be discussed. As the whole field of transition metal-catalyzed C(sp3)H functionalization keeps moving forward, more synthetically useful chemo-, regio-, diastereo-, and enantioselective reactions catalyzed by transition-metal with bidentate directing group coordination will be discovered in the future and this promising and attractive strategy will play a more critical role in modern organic synthesis.

The direct transformation of unactivated C(sp(3))-H bonds into C-halogen bonds was achieved by palladium catalysis at room temperature with good functional group tolerance. Some drugs and natural products were readily modified by this method. Merged with substitution reaction, newly formed C-X bonds can be transformed into diverse C-O, C-S, C-C and C-N bonds. A preliminary mechanism study demonstrates that solvent is crucial for C-H activation and the C-H activation step is involved in the rate-limiting step. An isolated Pd(ii) intermediate can be transformed into a halogenated product with the retention of conformation which suggests that concerted reductive elimination from Pd(iv) to form a C-X bond was favored.

In the past decade, transition-metal-catalyzed C-H functionalization by weak coordination has emerged as a practical and powerful tool to access many valuable chemicals. Two classes of weakly coordinating directing groups, commonly occurring functional groups, and easily removable auxiliaries, have been found to be efficient and practical for C-H activation reactions. This mini-review contains examples of recent research advances on transition-metal-catalyzed SP2 C-H functionalization via weak coordination, using Ru, Rh, and Pd. A number of weakly coordinating functional groups (e.g., ketone, ester, carbamate, tertiary amide, ether, thioether, alcohol, and some others) are covered. As the field of transition-metal-catalyzed C-H functionalization continues to develop and more synthetically useful chemo-, regio-, and enantioselective reactions catalyzed by transition metal via weak coordination are discovered, this promising and attractive strategy will play a more important role in modern organic synthesis.

All the hype: The title reaction has been developed for the facile synthesis of a variety of complex alkyl ethers. Cyclic hypervalent iodine (I(3+) ) reagents serve as oxidants for this unique CH alkoxylation reaction. The reaction demonstrates excellent reactivity, good functional-group tolerance, and high yields. Q=8-aminoquinoline-derived auxiliary.

In recent years, transition metal-catalyzed C(sp3)H functionalization has gradually emerged as a practical and powerful tool to prepare highly valuable chemicals. In this mini-review, we will give some examples to cover recent research advances on transition-metal (Pd, Ni) catalyzed C(sp3)H functionalization via bidentate directing group coordination. Different bidentate directing groups will be discussed. As the whole field of transition metal-catalyzed C(sp3)H functionalization keeps moving forward, more synthetically useful chemo-, regio-, diastereo-, and enantioselective reactions catalyzed by transition-metal with bidentate directing group coordination will be discovered in the future and this promising and attractive strategy will play a more critical role in modern organic synthesis.

Acid brings the oxygen: a general method for palladium-catalyzed C-H oxygenation has been developed for the facile synthesis of a wide range of functionalized phenols with readily available aryl ketones, benzoates, benzamides, acetanilides, and sulfonamides. A trifluoroacetic acid/trifluoroacetic acid anhydride solvent system serves as the oxygen source and is the critical factor for C-H activation.

The carbamate group is found to be superior over esters and ketone groups in terms of directing ability in the hydroxylation reactions providing catechol and pyrogallol derivatives with excellent regioselectivity.

This novel title method gives access to a wide range of C(sp3)-H alkoxylation products with excellent regioselectivity and with high yields.

A novel and efficient synthesis of 2-aminophenols, 2-aminobenzene-1,3-diols, and heterocycles through Ru-catalyzed C–H mono- and dihydroxylation of anilides has been developed with a new directing group strategy. The reaction demonstrates excellent reactivity, regioselectivity, good functional group tolerance, and high yields.

Excellent reactivity, ortho-selectivity, good functional group tolerance, and high yields are demonstrated for the title reaction.

A novel and efficient synthesis of 2-aminophenols, 2-aminobenzene-1,3-diols, and heterocycles through Ru-catalyzed C–H mono- and dihydroxylation of anilides has been developed with a new directing group strategy. The reaction demonstrates excellent reactivity, regioselectivity, good functional group tolerance, and high yields.