Hydrogen production coupled with water and organic oxidation based on layered double hydroxides

Abstract

Hydrogen production via electrochemical water splitting is one of the most green and promising ways to produce clean energy and address resource crisis, but still suffers from low efficiency and high cost mainly due to the sluggish oxygen evolution reaction (OER) process. Alternatively, electrochemical hydrogen-evolution coupled with alternative oxidation (EHCO) has been proposed as a considerable strategy to improve hydrogen production efficiency combined with the production of high value-added chemicals. Although with these merits, high-efficient electrocatalysts are always needed in practical operation. Typically, layered double hydroxides (LDHs) have been developed as a large class of advanced electrocatalysts toward both OER and EHCO with high efficiency and stability. In this review, we have summarized the latest progress of hydrogen production from the perspectives of designing efficient LDHs-based electrocatalysts for OER and EHCO. Particularly, the influence of structure design and component regulation on the efficiency of their electrocatalytic process have been discussed in detail. Finally, we look forward to the challenges in the field of hydrogen production via electrochemical water splitting coupled with organic oxidation, such as the mechanism, selected oxidation as well as system design, hoping to provide certain inspiration for the development of low-cost hydrogen production technology.

Layered Double Hydroxide Catalysts Preparation, Characterization and Applications for Process Development: An Environmentally Green Approach

“…There are enormous applications of LDHs catalysts, with few examples used as support for different catalytic materials [3-5] and as catalysts for organic transformations such as epoxidation reaction of olefins (styrene, cyclohexene) Mg-Al hydrotalcite [6], Aldol and Knoevenagel condensation Ni-Al hydrotalcite [7], Heck-Suzuki reaction Mg Al-LDH-Pd° [8], hydroxylation of phenol, Michael reaction, transesterification CoNiAl hydrotalcite, LDHs as oxidation catalysts [9][10][11] and CO2 absorbents [9], anion exchangers Ni-Al-LDH-Sn [10]. LDHs has vast applications in the area of environmental catalysis (Table 1), CuMgAl LDHs, which can be used in diesel engine soot [11][12][13], ion exchange/adsorption [14], drugs-Levodopa LDH nano composite shows minimal toxicity potential of a PC12 cell Parkinson's disease model in a dose [15], anti-cancer nano medicine [16], Lysozyme-LDH for antimicrobial activity [17], MgFe LDH-Mo can be used for degradation of methyl orange by photochemical method [18], Iron(III) Porphyrin MgAl LDHs [19,20], electroactive and photoactive materials MgAlCu Hydrotalcite [12], electrochemistry [21,22], fuel cell, and water splitting [22][23][24][25][26], LDHs carbon nano composites Ni/Co supercapacitors [27], Mg Al LDHs nano flakes humic acid adsorption [28], Biochar-Fe LDH for phenol removal [29], waste water treatment [30], LDHs nano carriers for drug delivery [31], LDHs based nano systems for cancer therapy [32], NiCo2S4@NiFe LDH hollow spheres as electrocatalysts [33]. Many reviews have been published focusing over particular examples, i.e.…”

Layered Double Hydroxides for Oxygen Evolution Reaction towards Efficient Hydrogen Generation

“…The research of active sites not only guides researchers to create plentiful sites for OER through controlling synthesis conditions and modified strategies but also helps to optimize the electron structures to improve the electron transfer capability. To date, plenty of reviews have summarized the synthesis strategies, structural characters, and electrochemical performance for the LDHs and their derivatives [25][26][27][28][29], but only few reviews mention about the recognition and the assignment of active sites in LDHs during water splitting. Therefore, the latest research progress with respect to the LDHs electrocatalysts for water splitting has been concluded in this review.…”

Ru-doping induced lattice strain in hetero-phase Ni2P–Ni12P5arrays enables simultaneous efficient energy-saving hydrogen generation and formate electrosynthesis

“…5,6 An innovative strategy to address these challenges is utilizing another thermodynamically more favorable anodic reaction than the OER to couple with the HER for reducing the energy input, and ideally, simultaneously producing hydrogen at the cathode and other high-value chemicals at the anode. [7][8][9][10][11][12] As a low-toxicity byproduct of biodiesel production and soap manufacturing, glycerol is a potential raw material for the production of various value-added chemicals by oxidation. Moreover, the glycerol oxidation reaction (GOR) is thermodynamically more favorable in comparison with the OER, making it an ideal alternative to replace the OER to assemble hybrid water electrolysis systems with low operating cell voltage.…”