Promising Liquid Organic Hydrogen Carrier Research Articles

Benzyl-methylbenzyl-benzene: Improving hydrogen storage and release performance of dibenzyltoluene based liquid organic hydrogen carrier

Liquid organic hydrogen carrier (LOHC) technology enables the safe, easy, and cost-effective storage and transportation of large quantities of hydrogen using inexpensive and mass-produced compounds. The LOHC materials play a crucial role in hydrogen storage capacity, reaction kinetics, reaction temperature, and reversibility. However, the development and optimization of LOHC materials is limited due to using of mass-produced materials for bulk hydrogen logistics. Herein, we propose a molecular engineering approach to overcome the limitations of commercial dibenzyltoluene (DBT)-based LOHC systems, considered one of the most promising LOHC materials based on the heat transfer oil, Marlotherm SH (MSH), owing to its superior physical properties (wide liquid range, and non-flammable properties), low price, and low toxicity. We devised a new chemical structure, benzyl-methylbenzyl-benzene (BMB), with highly improved dehydrogenation/hydrogenation performance achieved by rearranging the methyl group of DBT to overcome the limitations of slow reaction kinetics in terms of its chemical structure. The BMB exhibits a 150 % faster hydrogenation than MSH at 150 °C, and it releases 170 % more hydrogen compared to DBT at 270 °C. In addition, we analyzed the dehydrogenation/hydrogenation pathways according to the structures of DBT and BMB. Furthermore, we found that BMB (27 %) is inevitably generated in the MSH synthesis process alongside DBT (73 %). Based on this, we propose a streamlined and sustainable engineered method for improved MSH material manufacturing with a high BMB ratio (∼70 %). The scientific findings provide a fundamental understanding of DBT-based LOHC systems and new insights into the design of novel LOHC candidates.

Active and stable Pt-Ga2O3/Al2O3 catalyst for dehydrogenation of methylcyclohexane

Methylcyclohexane (MCH) is considered as one of the most promising liquid organic hydrogen carriers (LOHCs) in terms of hydrogen storage and delivery. However, the dehydrogenation process of MCH is relatively difficult, which requires catalyst having high activity and stability. In this work, a catalyst of Pt/Al2O3 by doping Ga2O3 was prepared and tested in the dehydrogenation of MCH, resulting in both high activity and stability. After 176 h of the reaction, the conversion of MCH is no significant decrease, and the toluene (TOL) selectivity was greater than 99%. The characterization results of the catalyst evidenced that the excellent performance of the catalyst is due to the introduction of Ga2O3, which prevents the growth of Pt species and results more positively charged Pt species. These Pt species can weaken the strength of the adsorption between Pt and dehydrogenation products, making dehydrogenation products more easily to be desorbed, which achieving high activity and stability. The catalyst shows great potential for industrial application in the future. This work provides theoretical guidance for designing highly stable dehydrogenation catalysts.

Anchoring PdAu nanoclusters inside aminated metal-organic framework for fast dehydrogenation of formic acid

Liquid sunshine formic acid (FA), which is obtainable through CO2 hydrogenation with green H2 or biomass processing, is regarded as a prospective liquid organic hydrogen carrier (LOHC) owing to its high volumetric capacity (53 g H2 L−1), stability, and renewability. The search for effective catalysts to produce H2 from additive-free FA under ambient conditions is necessary but remains a challenge. Herein, highly dispersed and ultrafine PdAu nanoclusters (NCs) (1.2 nm) anchored by the aminated metal–organic framework (NH2-MIL-101) were successfully fabricated using a facile wet-chemical method and employed as a superior catalyst for formic acid dehydrogenation (FAD). The resulting PdAu/NH2-MIL-101 catalyst demonstrates 100 % H2 selectivity and superior performance with a turnover frequency value reaching 2921.0 h−1 at 323 K without any additive. Under similar conditions, this value is higher than the majority of published MOF-based FAD heterogeneous catalysts. The superior performance of PdAu/NH2-MIL-101 originates from a synergistic combination of the promoting effect of amino groups, the effective electronic coupling of Pd and Au, and the strong metal-support interaction between PdAu NCs and NH2-MIL-101, which promote the formation of reactive PdAu NCs and thus greatly improve catalytic performance. This work may provide important inspiration for developing highly efficient catalysts and strongly promote FA as a promising LOHC for chemical H2 storage.

Maximizing clean hydrogen release from perhydro-benzyltoluene: Energy-efficient scale-up strategies and techno-economic analyses

We present a highly efficient method for hydrogen release from perhydro-benzyltoluene (H12-BT), one of the most promising liquid organic hydrogen carriers (LOHCs) in the current energy landscape. Despite the demand for scalability, dehydrogenation of H12-BT has so far only been subject to published studies on batch reactors at the laboratory scale. Here, we establish a continuous bench-scale 2.3 Nm3-H2/h-level (5 kg-H2/day) catalytic dehydrogenation system using H12-BT. Parametric analysis provides insights into operational and design strategies for large-scale H12-BT dehydrogenation systems. The proposed model for the system energy analysis enables outlining a path to elevate the round-trip efficiency (RTE). The basis of this is the incorporation of well-managed thermal systems and hydrogenation-based power generation, such as solid oxide fuel cells (SOFCs) and combined cycle gas turbines (CCGTs). These strategies, quantitatively assessed, demonstrate the feasibility above 70 %. Through techno-economic analyses (TEA), the dehydrogenation cost reduction associated with efficiency improvement is assessed, showing up to approximately 11.8 % cost reduction. This study propels efficient dehydrogenation system advancement, fostering a sustainable hydrogen supply within the global chain.

Preparation of MCM-41 supported Ni@Pd core-shell nanocatalysts by ultrasound-assisted galvanic replacement and their efficient catalytic dehydrogenation of dodecahydro-N-ethylcarbazole

N-ethylcarbazole (NEC) is one of the most promising liquid organic hydrogen carriers (LOHCs) due to its low dehydrogenation enthalpy. The development of an efficient catalyst for the dehydrogenation of dodecahydro-N-ethylcarbazole (H12-NEC) is the key to the large-scale application of LOHCs. In this paper, Ni/MCM-41 was prepared by chemical reduction method using MCM-41 as the carrier, and then MCM-41 loaded Nin@Pd1 core-shell nanocatalysts (Nin@Pd1/M41) were prepared by ultrasound-assisted galvanic replacement method using Ni as the templating agent and reducing agent. It was shown that there was electron transfer between Ni and Pd, and SMSI effect of Nin@Pd1 with MCM-41 by the characterization results of Nin@Pd1/M41, which promoted the catalytic performance. H12-NEC dehydrogenation efficiency over Ni6@Pd1/M41 reached 100% at 180 °C for 4 h and at 170 °C for 6 h, and 97.58% for 6 h at 160 ℃, and TOF was 5080.6 h−1, which was better than that reported in the literature. The excellent catalytic dehydrogenation performance of Ni6@Pd1/M41 can mainly be attributed to the synergistic effect of coordination and strain effects between the bimetals.

Carbon bowl-confined subnanometric palladium-gold clusters for formic acid dehydrogenation and hexavalent chromium reduction

Formic acid (FA), a high-value product of CO2 hydrogenation and biomass conversion, is considered a promising liquid organic hydrogen carrier for its high hydrogen content, easy accessibility, and relative stability. The development of an efficient heterogeneous catalyst toward FA dehydrogenation and Cr(VI) reduction by FA is needed to boost its sluggish kinetics but still remains a challenge. Herein, uniformly dispersed subnanometric PdAu alloy clusters (i.e., 0.9 nm) were successfully prepared and confined by amine-functionalized carbon bowls (ACB). By virtue of the tiny size and abundant active sites of PdAu clusters, the promotional effect of surface amine groups, and electronic interaction between subnanometric PdAu clusters and support, this as-prepared PdAu/ACB catalyst exhibits superior catalytic property for additive-free FA dehydrogenation (turnover frequency, 10597 h−1 at 323 K) and Cr(VI) reduction (rate constant, 0.47 min−1 at 298 K) under mild conditions, higher than most of the catalysts reported so far. This study offers insight into the design of efficient and durable catalysts for various catalytic applications in energy and environment.

Enhanced Activity of WOx-Promoted PdNi Nanoclusters Confined by Amino-Modified KIT-6 for Dehydrogenation of Additive-Free Formic Acid

Formic acid (FA, HCOOH), featured as a major liquid product of biomass processing and especially a liquid sunshine carrier, thus becomes a renewable and promising liquid organic hydrogen carrier. It is highly desirable, but it remains a big challenge to develop a highly active heterogeneous catalyst with no or low content of noble metals for dehydrogenation of additive-free FA at ambient conditions. Herein, for the first time, WOx-modified PdNi alloy nanoclusters immobilized by amino-functionalized KIT-6 (PdNi-WOx/KIT-6-NH2) are prepared through a simple and facile strategy at ambient conditions. PdNi-WOx clusters with an ultrasmall size of 1.4 nm are highly dispersed onto KIT-6-NH2 support. The strong electronic coupling in PdNi-WOx NCs and electronic metal–support interaction between PdNi-WOx NCs and KIT-6-NH2 support lead to the formation of electron-rich PdNi of PdNi-WOx/KIT-6-NH2. The resulting PdNi-WOx/KIT-6-NH2 catalyst exhibits highly efficient catalytic activity and 100% hydrogen selectivity for formic acid dehydrogenation without extra additives, giving turnover frequency (TOF) values of 1699 h–1 at 303 K and 4417 h–1 at 323 K, which is higher than most of the heterogeneous catalysts ever reported. Kinetic isotope effect investigation clearly shows that C–H bond cleavage is the rate-determining step for PdNi-WOx/KIT-6-NH2. This work provides a new insight into designing low-cost and efficient heterogeneous catalysts for dehydrogenation of formic acid.

Trace ultrafine Ru nanoparticles on Ni/Al hydrotalcite-derived oxides supports as extremely active catalysts for N-ethylcarbazole hydrogenation

Liquid organic hydrogen carriers (LOHCs) is a promising hydrogen storage technology and has become a hot issue. However, there is still a shortage of LOHCs hydrogenation catalysts that can balance cost and catalytic performance. In this work, a series of Ni/Al hydrotalcite-derived oxides (LDOs) were prepared with different Ni/Al ratios and preparation methods, on which trace ultrafine Ru nanoparticles (0.5 wt%, 1 wt%, 1.5 wt%) were supported. The activities were investigated for the hydrogenation of N-ethylcarbazole (NEC), one of the most promising liquid organic hydrogen carriers. Characterizations including XRD, XPS, SEM, TEM and H2-TPR indicate the composition of Ni/Al-LDOs and reveal three kinds of Ni/Al interactions existed in Ni/Al-LDOs. The influences of Ni-Al interactions on the size of Ru NPs supported on Ni/Al-LDOs and on the NEC hydrogenation activity were also explored. The results show that 1.5 wt% Ru-Ni1Al2-LDO300 has the best catalytic performance for NEC hydrogenation, with which can achieve up to 5.5 wt% hydrogen absorption at 150℃ and 8 MPa for 12 min, and the yield of 12H-NEC can reach 100 % for 60 min. In other words, the catalytic performance of 1.5 wt% Ru supported catalyst is superior to 5 wt% Ru/Al2O3 catalyst commonly used for NEC hydrogenation. This work provides a new idea for preparing catalysts with low cost and high performance by tuning the structure of Ni/Al-LDO supports and the size of Ru NPs.

Efficient Pd on carbon catalyst for ammonium formate dehydrogenation: Effect of surface oxygen functional groups

Formate solution is a promising liquid organic hydrogen carrier but suffers from kinetic challenges. This study investigates the kinetics of the surface-functionalized Pd on carbon catalysts for formate dehydrogenation and the impact of O-functional groups. The fraction of the distinguished O-functional groups was modulated by the different concentrated HNO3 solutions treatment or by H2 reduction. This study shows that the O-functional groups play critical roles in dispersing Pd nanoparticles and decreasing the activation energy for dehydrogenation. Density functional theory (DFT) calculation reveals that most O-functional groups enhance formate adsorption on the Pd active site. However, the existence of CO groups consumes reducing agents and hinders the formation of metallic Pd. The electron transfer from Pd to oxygen functional groups is unfavorable to dehydrogenation. The as-prepared Pd5/re-ACA (reduced activated carbon washed by acid) exhibited significant activity with a higher turnover frequency of 13,511 h−1 than commercial Pd/C.

Selective Photocatalytic Dehydrogenation of Formic Acid by an In Situ-Restructured Copper-Postmetalated Metal-Organic Framework under Visible Light.

Formic acid is considered as one of the most promising liquid organic hydrogen carriers. Its catalytic dehydrogenation process generally suffers from low activity, low reaction selectivity, low stability of the catalysts, and/or the use of noble-metal-based catalysts. Herein we report a highly selective, efficient, and noble-metal-free photocatalyst for the dehydrogenation of formic acid. This catalyst, UiO-66(COOH)2-Cu, is built by postmetalation of a carboxylic-functionalized Zr-MOF with copper. The visible-light-driven photocatalytic dehydrogenation process through the release of hydrogen and carbon dioxide has been monitored in real-time viaoperando Fourier transform infrared spectroscopy, which revealed almost 100% selectivity with high stability (over 3 days) and a conversion yield exceeding 60% (around 5 mmol·gcat–1·h–1) under ambient conditions. These performance indicators make UiO-66(COOH)2-Cu among the top photocatalysts for formic acid dehydrogenation. Interestingly, the as-prepared UiO-66(COOH)2-Cu hetero-nanostructure was found to be moderately active under solar irradiation during an induction phase, whereupon it undergoes an in-situ restructuring process through intraframework cross-linking with the formation of the anhydride analogue structure UiO-66(COO)2-Cu and nanoclustering of highly active and stable copper sites, as evidenced by the operando studies coupled with steady-state isotopic transient kinetic experiments, transmission electron microscopy and X-ray photoelectron spectroscopy analyses, and Density Functional Theory calculations. Beyond revealing outstanding catalytic performance for UiO-66(COO)2-Cu, this work delivers an in-depth understanding of the photocatalytic reaction mechanism, which involves evolutive behavior of the postmetalated copper as well as the MOF framework over the reaction. These key findings pave the way toward the engineering of new and efficient catalysts for photocatalytic dehydrogenation of formic acid.

Preliminary feasibility study for hydrogen storage using several promising liquid organic hydrogen carriers: Technical, economic, and environmental perspectives

Liquid organic hydrogen carriers (LOHC) are promising alternatives to conventional H2 media owing to their novelty in the storage and transportation of H2. Herein, a comprehensive feasibility study is reported for hydrogenation processes using several promising LOHC systems: N-ethylcarbazole (NEC)–perhydro-NEC (12H-NEC), dibenzyltoluene (DBT), perhydro-dibenzyltoluene (18H-DBT), toluene (TOL)–methylcyclohexane (MCH), and CO2–methanol (MeOH). Detailed process simulation using Aspen Plus® reveals a considerable amount of stored H2 for DBT–18H-DBT (7.20 kmolH2 h−1) and the lowest unit cost of H2 storage (7.00 $ kgH2-1) by itemized cost estimation. In addition, the effects of operating temperature, recycle ratio of unreacted H2, and scale of H2 storage on economic feasibility are investigated, and the expected cost reductions to 2.83, 4.21, 3.84, and 2.37 $ kgH2-1 are evaluated for NEC–12H-NEC, DBT–18H-DBT, TOL–MCH, and CO2–MeOH, respectively. The sensitivity analysis quantifies the variation in the total unit cost of H2 storage and identifies the costs of the H2 reactant and labor as key economic parameters in LOHC hydrogenation. Furthermore, 0.16–0.43, 0.78–1.72, 1.25–1.73, and 1.12–5.52 kgCO2 kgH2-1 of unit CO2 emissions are evaluated by integrative carbon footprint analysis.

Comprehensive thermodynamic study of alkyl-biphenyls as a promising liquid organic hydrogen carriers

Finding suitable hydrogen carriers is a real challenge for science and engineering. Alkyl-biphenyls have sufficient hydrogen storage density and are not expensive. Experimental and theoretical thermochemical studies (vapour pressure measurements and combustion calorimetry) of mono- and di-alkyl-substituted biphenyls were carried out. The standard molar vaporization enthalpies were derived from the temperature dependence of the vapor pressures measured by the transpiration method. The thermodynamic data on phase transitions (crystal-gas, crystal-liquid, and liquid–gas) available in the literature were collected and evaluated. High-level quantum-chemical methods (G3MP2 and G4) were used both to check the experimental values of the enthalpies of isomerization reactions and to estimate the enthalpies of hydrogenation/dehydrogenation reactions of mono- and di-alkyl-substituted biphenyls.

Energetics of Technical Integration of 2‐Propanol Fuel Cells: Thermodynamic and Current and Future Technical Feasibility

2‐Propanol/acetone is a promising liquid organic hydrogen carrier system for fuel cell reactions. Herein, six different concepts for a 2‐propanol/acetone fuel cell system are evaluated in MATLAB simulation with respect to their thermodynamic integration and technical feasibility. Four of the concepts use a direct 2‐propanol fuel cell while the other two first release molecular hydrogen from 2‐propanol and subsequently use a hydrogen fuel cell. The presented liquid phase 2‐propanol fuel cell concept is thermodynamically feasible but cannot be realized technically using commercial Nafion membranes, due to membrane dissolution by the 2‐propanol/acetone/water fuel mixture. Gaseous 2‐propanol fuel cells imply a high heating requirement for the evaporation of the fuel. A direct high‐temperature fuel cell using 2‐propanol is thermodynamically feasible because there is less water in the overall system but is not technically feasible because of the esterification of phosphoric acid. A very interesting option is the conversion of gaseous 2‐propanol to pressurized hydrogen in an electrochemical pumping step followed by a hydrogen fuel cell, because here the waste heat of a sufficiently hot hydrogen fuel cell can drive the 2‐propanol evaporation.

Development of an efficient Pt/SiO2 catalyst for the transfer hydrogenation from perhydro-dibenzyltoluene to acetone

The storage of hydrogen in liquid organic hydrogen carriers (LOHCs) represents a safe and easy to handle storage solution for energy from renewable sources. Dibenzyltoluene (H0-DBT)/perhydro-dibenzyltoluene (H18-DBT) is a promising LOHC system due to its low flammability, wide liquid range and high storage density for hydrogen. However, this LOHC system requires high temperature heat (typically > 250 °C) for hydrogen release, which lowers the efficiency of the storage cycle if no appropriate source of waste heat is available. This disadvantage can be mitigated by transfer of the hydrogen onto an acceptor molecule such as acetone at mild temperatures, forming isopropanol which can be used as fuel in direct fuel cell concepts or represents a valuable chemical product. Herein, we present the development of an active and selective platinum on silica (Pt/SiO2) catalyst for the transfer hydrogenation of acetone using perhydro-dibenzyltoluene as the sole source of hydrogen. Relevant catalyst design parameters, such as the optimal pore size, Pt loading, reduction and oxidation temperatures/times, are identified and their influence on the catalyst morphology and performance is discussed.

Dehydrogenation of dodecahydro-N-ethylcarbazole over spinel supporting catalyst in a continuous flow fixed bed reactor

Dodecahydro-N-ethylcarbazole (12H-NECZ) is considered as one of the most promising liquid organic hydrogen carriers (LOHCs) in terms of hydrogen storage and delivery. Developing dehydrogenation catalysts with high efficiency is of significance for its application on a large scale. Herein, we reported a work on the dehydrogenation of 12H-NECZ over supported spinel catalysts in a continuous flow fixed bed reactor. The influence of active metal of Pt, Pd and Ru was firstly investigated. Then four kinds of spinel (MgAl2O4, NiAl2O4, CoAl2O4 and ZnAl2O4) supporting Pd catalysts were well studied. Pd/MgAl2O4 showed the best performance with a conversion of 98.3% at 180 °C. The characterizations of catalysts evidenced that the good performance was attributed to the strong interaction between Pd and MgAl2O4, which resulted in the smaller Pd particles and more positively charged Pd species. These Pd species were believed to be beneficial for dehydrogenation via weakening the adsorbed strength between Pd and dehydrogenated products. This work provides theoretical guidance for the design of efficient dehydrogenation catalysts.

Efficient production of hydrogen from a valuable CO2-derived molecule: Formic acid dehydrogenation boosted by biomass waste-derived catalysts

Formic acid has been postulated as one of the most promising liquid organic hydrogen carriers. Numerous studies dealing with the development of efficient catalysts able to boost the dehydrogenation of formic acid can be found in recent literature. However, most of them lack in stability, so that finding stable catalysts is highly desirable yet challenging. In the present study, we developed Pd-based biomass-derived carbon-supported catalysts by following a simple protocol. The effect of the modification of both the metal phase and support has been assessed by incorporating Ag in the form of bimetallic nanoparticles and nitrogen functional groups, respectively. The effect of the method followed for the preparation of the catalysts was also checked. It has been found that the resulting PdAg-based catalysts supported on N-doped biomass-derived carbon materials showed suitable activity and excellent stability under reaction conditions. The present study highlights the potential of modulating the features of the catalysts, not only in terms of the composition of the metal phase and incorporation of heteroatoms in the support, but also in terms of the synthetic protocol used.

Ultrasonic-assisted synthesis of highly stable RuPd bimetallic catalysts supported on MgAl-layered double hydroxide for N-ethylcarbazole hydrogenation.

N-Ethylcarbazole (NEC), as a promising liquid organic hydrogen carrier (LOHC), can store and release hydrogen through a reversible catalytic hydrogenation and dehydrogenation reaction. In this paper, RuPd bimetallic nanocatalyst supported on MgAl-layered double hydroxide (RuPd/LDH) was prepared by ultrasonic-assisted reduction method, and its catalytic performance in NEC hydrogenation was also studied. Under the action of ultrasound, hydroxyl groups (-OH) on the surface of LDH support dissociated into highly reductive hydrogen radicals for the reduction of Ru3+ and Pd2+ to Ru0 and Pd0. For the 4Ru1Pd/LDH-(300-1) catalyst prepared under ultrasonic conditions of 25 kHz, 300 W, and 1 h, the average size of the metal nanoparticles was only 1.23 nm, which indicated that Ru, Pd, and RuPd NPs were highly dispersed on the support. The strong electronic effects between Ru and Pd improved its catalytic performance in NEC hydrogenation. With m(Ru+Pd)/m(NEC) = 0.2wt%, pressure of 6 MPa, and temperature of 120 °C, the selectivity of dodecahydro-N-ethylcarbazole (12H-NEC) was 98.07%, and the capacity and percentage of hydrogen storage were 5.75wt% and 99.3%, respectively. After the catalyst was recycled 8 times, the percentage of hydrogen storage still reached 98.9%, showing higher stability. The preparation method is simple and environmentally friendly, providing an idea for the preparation of ultrafine bimetallic catalysts with high catalytic activity and stability.

N-doped graphitized carbon supported Co@Ru core–shell bimetallic catalyst for hydrogen storage of N-ethylcarbazole

We investigate the hydrogenation of one promising liquid organic hydrogen carrier N-ethylcarbazole on the N-doped graphitized carbon (NGC) supported Co@Ru core–shell bimetallic catalyst.

Enhanced activity of a WOx-incorporated Pt/Al2O3 catalyst for the dehydrogenation of homocyclic LOHCs: Effects of impregnation sequence on Pt–WOx interactions

This study focused on the development of catalysts for the dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) and perhydro-benzyltoluene (H12-BT), which are promising liquid organic hydrogen carriers (LOHCs). The reaction was performed at a low temperature to ensure hydrogen purity and catalyst durability, and the incorporation of WOx into Pt/Al2O3 was investigated to improve the low-temperature activity of the Pt/Al2O3 catalyst. WOx-incorporated Pt/Al2O3 catalysts with superior performance compared to that of the Pt/Al2O3 catalyst were developed by controlling the amount of incorporated WOx and the impregnation sequence of metals during catalyst preparation. TEM, chemisorption, and XPS analyses assisted in confirming the changes in the structure and electron density of the active material in accordance with the impregnation sequence and the amount of incorporated WOx; moreover, these factors were found to influence the catalyst performance. The electron-donating ability of W was determined according to the impregnation sequence of the metals, and confirmed by XPS analysis and the experimental reaction results. A DFT study on a hypothetical model containing WOx confirmed the donation of electrons from W to Pt, which was consistent with the experimental results. In addition, the H12-BT dehydrogenation on the investigated catalyst was kinetically more favorable compared to that on the Pt/Al2O3 catalyst, resulting in an enhancement of the dehydrogenation activity.

Utilizing Hydrogen Underpotential Deposition for Carbon Monoxide Reduction to Formaldehyde

Formaldehyde is an essential building block for hundreds of chemicals and a promising liquid organic hydrogen carrier (LOHC), yet its indirect energy-intensive synthesis process prohibits it from playing more significant role. Here we report a direct CO reduction to formaldehyde (CORTF) process that hybridizes thermal and electro-catalysis and utilizes hydrogen underpotential deposition property to overcome thermodynamic barrier and scaling relationship restriction. Using molybdenum phosphide as catalyst, formaldehyde can be produced with nearly 100% Faradaic efficiency in aqueous KOH solution, with its formation rate being one order of magnitude higher compared with state-of-the-art thermal catalysis approach. Simultaneous tuning of current density and reaction temperature leads to more selective and productive formaldehyde synthesis, confirming the effectiveness of “hybrid” approach. DFT calculations reveal that desorption of *H2CO intermediate likely serves as rate-limiting step, and the participation of H2O turns the reaction into thermodynamically favorable. Furthermore, a full-cell reaction set-up was demonstrated with CO hydrogenation to HCHO being achieved without any energy input, which shows the spontaneous potential of the reaction. Our study shows the advantage of hybridizing thermal and electro-catalysis in realizing thermodynamics and scaling relation confined reaction, which could serve as a new strategy in future reaction design.