Activation Energy For Desorption Research Articles

Enhanced hydrogen properties of MgH2 by Fe nanoparticles loaded hollow carbon spheres

In the present investigation, we have reported the synergistic effect of Fe nanoparticles and hollow carbon spheres composite on the hydrogen storage properties of MgH2. The onset desorption temperature for MgH2 catalyzed with hollow carbon spheres and Fe nanoparticle (MgH2-Fe-HCS) system has been observed to be 225.9 °C with a hydrogen storage capacity of 5.60 wt %. It could be able to absorb 5.60 wt % hydrogen within 55 s and desorb 5.50 wt % hydrogen within 12 min under 20 atm H2 pressure at 300 °C. The desorption activation energy of MgH2-Fe-HCS has been found to be 84.9 kJ/mol, whereas the desorption activation energies for as received MgH2, Hollow carbon sphere catalyzed MgH2 and Fe catalyzed MgH2 are found to be 130 kJ/mol, 103 kJ/mol, and 94.2 kJ/mol respectively. MgH2-Fe-HCS composite lowered the change in enthalpy of hydrogen desorption from MgH2 by 20.02 kJ/mol as compared to pristine MgH2. MgH2-Fe-HCS shows better cyclability up to 24 cycles of hydrogenation and dehydrogenation of MgH2. The mechanism for the better catalytic action of Fe and HCS on MgH2 has also been discussed.

Quantitative hydrogen trap states on high-angle grain boundaries and at dislocations in iron

Low-temperature thermal desorption spectrometry (L-TDS), by which specimens can be heated from -200 °C, was used to quantitatively evaluate the hydrogen desorption peak temperatures (Tp), the hydrogen desorption activation energies (Ea), and the hydrogen occupation ratios (θ) of high-angle grain boundaries and dislocations in iron. Cold-rolled iron was subjected to recrystallization and grain growth to produce three kinds of specimens with different areas of high-angle grain boundaries, in which low-angle grain boundaries were annihilated. L-TDS spectra of specimens containing dislocations and high-angle grain boundaries displayed two hydrogen desorption peaks, denoted as Peak 1 and Peak 2. Peak 1 corresponded to dislocations and displayed Tp, Ea, and θ values of 23 °C, 28.6 kJ·mol−1, and 1.1 to 2.7 atom·nm−1, respectively. In contrast, Peak 2 corresponded to high-angle grain boundaries and displayed Tp, Ea, and θ values of 85 °C, 43.7 kJ·mol−1, and 2.3 to 2.9 atom·nm−2, respectively.

Isotope effect on hydrogen storage properties of Ti and Nb co-substituted ZrCo alloy

In our previous study, we showed that the anti-disproportionation properties of Zr0.8Ti0.2-xNbxCo alloys were remarkably improved by the co-substitution of Zr with Ti and Nb. However, the practical application of these alloys in handling of hydrogen isotopes necessitates the first hand knowledge of hydrogen isotope effect. Herein, we discuss the hydrogen isotope effect on storage properties of Zr0.8Ti0.2-xNbxCo alloys. According to PCT measurements on desorption of deuterium from the Zr0.8Ti0.2-xNbxCo deuterides and comparison with corresponding hydrides, the deuterides require relatively lower temperature to achieve the desired equilibrium pressure. DSC measurements reveal a significant decrease in the activation energy for hydrogen/deuterium desorption reactions when Zr is substituted with Ti and Nb. Furthermore, it is observed that the activation energy of deuterium desorption is lower than the desorption of hydrogen from analogous hydride. Isotope effect on isothermal disproportion studies on Zr0.8Ti0.2-xNbxCo-deuterides divulge that Zr0.8Ti0.2-xNbxCo-deuterides have superior anti-disproportionation properties over corresponding hydrides, and further improvement is anticipated for the Zr0.8Ti0.2-xNbxCo-tritides. This study revealed the significant impact of Ti and Nb co-substitution on hydrogen isotope storage properties of Zr0.8Ti0.2-xNbxCo alloys, making them potential candidates for handling hydrogen isotopes.

Microstructural characteristics and hydrogen storage properties of the Mg–Ni–TiS2 nanocomposite prepared by a solution-based method

Magnesium hydride is considered as a promising solid-state hydrogen storage material due to its high hydrogen capacity. How to improve hydrogen desorption kinetics of MgH2 is one of key issues for its practical applications. In this study, we synthesize a Mg–Ni–TiS2 composite through a solution-based synthetic strategy. In the as-prepared composite, the co-precipitated Mg and Ni nanoparticles are highly dispersed on TiS2 nanosheets. As a result, the activation energy for hydrogen desorption decreases to 79.4 kJ mol−1. Meanwhile, the capacity retention rate is kept at the level of 98% and only slight kinetic deterioration is caused after fifty hydrogenation-dehydrogenation cycles. Further investigation indicates that the superior hydrogen desorption kinetics is attributed to the synergistically catalytic effect of the in situ formed Mg2NiH4 and TiH2, and the remained TiS2. The excellent cycle stability is related not only to the inhibition effect of the secondary phases on powder agglomeration and crystallite growth of Mg and MgH2 but also to the prevention effect of MgS and TiS2 on redistribution of catalytic Mg2NiH4 and TiH2 nanoparticles during cycling. This work introduces a feasible approach to develop Mg-based hydrogen storage materials.

Hydrogen Desorption Kinetics of V30Nb10(TixCr1–x)60 High-Entropy Alloys

In recent years, high-entropy alloys (HEAs) have attracted wide attention for their enormous hydrogen storage potential, fast hydrogen absorption kinetics, and a wide range of composition selectivity, and the fact that alloys with body-centered cubic (BCC) structure are considered to possess large capacity. Herein, three V30Nb10(TixCr1–x)60 HEAs with different Ti contents (Ti25, Ti30, Ti35) forming BCC structures were designed using the method of CALPHAD. The microstructure characteristics and the hydrogen storage performances, especially the kinetics of hydrogen desorption, were systematically investigated. The results show that after absorbing ~3.7 wt.% hydrogen at 300 K with 100 bar hydrogen pressure, the studied alloys exhibit similar hydrogen release behaviors at different temperatures. Taking the V30Nb10Ti25Cr35 alloy as an example, it was able to release 1.96 wt.%, 2.21 wt.%, and 2.48 wt.% of hydrogen at 353, 373, and 423 K, respectively. The higher the temperature, the faster the hydrogen desorption kinetics and the more hydrogen released. The hydrogen desorption kinetics of the alloys were successfully fitted with the Ginstling–Brounshtein model, and the main rate-controlling step was diffusion. In addition, the diffusion activation energy of hydrogen desorption decreases with the substitution of Cr content. The present study is expected to provide valuable information for the better development of high-entropy-based hydrogen storage alloys.

Microcantilever-Based In Situ Temperature-Programmed Desorption (TPD) Technique.

Temperature-programmed desorption (TPD) is an essential technique for characterizing the fundamental properties of advanced catalysts like catalytic activity and kinetics. However, the available TPD instruments are bulky and use ex situ detectors to measure the probe molecules in the elution gas flow. Herein, we demonstrate an in situ TPD technique by developing a silicon microcantilever that integrates functional elements for mass measuring and programmable sample heating. An only nanogram-level sample is required to load on the microcantilever free end, where the integrated microheater provides programmed temperatures and the desorption-induced mass change can be measured in situ. In situ TPD can continuously measure the number of desorbed molecules from the catalyst during programmed heating, without the need for ex situ detectors. With a single-time in situ TPD measurement, the desorption activation energy can be directly calculated. The proposed in situ TPD method outperforms the existing TPD techniques and is expected to enable next-generation TPD applications.

Different effect between KH and KOH additives on the hydrogen storage properties of MgH2 doped with graphene

The effect of KH on the hydrogen storage properties of MgH2 doped with graphene is investigated in this study, and compared with that of KOH. The results showed that MgH2 doped with 1 wt% KH and 1 wt% graphene has a significantly improved hydrogen storage performance. It desorbed 6.0 wt% H2 within 30 min at 300 °C, which is much faster than that of MgH2. However, its desorption rate is slower and its desorption activation energy is larger than those of the sample doped with KOH and graphene. The results showed the catalyst KMgH3 can be formed by the addition of either KH or KOH, so the different effect between KH and KOH might be due to the H-H exchange between KH and MgH2 which can suppress the desorption of MgH2, while the in-situ formed MgO by the addition of KOH can promote the desorption of MgH2.

On-Surface Synthesis and Evolution of Self-Assembled Poly(p-phenylene) Chains on Ag(111): A Joint Experimental and Theoretical Study.

The growth of controlled 1D carbon-based nanostructures on metal surfaces is a multistep process whose path, activation energies, and intermediate metastable states strongly depend on the employed substrate. Whereas this process has been extensively studied on gold, less work has been dedicated to silver surfaces, which have a rather different catalytic activity. In this work, we present an experimental and theoretical investigation of the growth of poly-p-phenylene (PPP) chains and subsequent narrow graphene ribbons starting from 4,4″-dibromo-p-terphenyl molecular precursors deposited at the silver surface. By combing scanning tunneling microscopy (STM) imaging and density functional theory (DFT) simulations, we describe the molecular morphology and organization at different steps of the growth process and we discuss the stability and conversion of the encountered species on the basis of calculated thermodynamic quantities. Unlike the case of gold, at the debromination step we observe the appearance of organometallic molecules and chains, which can be explained by their negative formation energy in the presence of a silver adatom reservoir. At the dehydrogenation temperature, the persistence of intercalated Br atoms hinders the formation of well-structured graphene ribbons, which are instead observed on gold, leading only to a partial lateral coupling of the PPP chains. We numerically derive very different activation energies for Br desorption from the Ag and Au surfaces, thereby confirming the importance of this process in defining the kinetics of the formation of molecular chains and graphene ribbons on different metal surfaces.

Zinc Phthalocyanine Sensing Mechanism Quantification for Potential Application in Chemical Warfare Agent Detectors.

Rapid and accurate detection of lethal volatile compounds is an emerging requirement to ensure the security of the current and future society. Since the threats are becoming more complex, the assurance of future sensing devices' performance can be obtained solely based on a thorough fundamental approach, by utilizing physics and chemistry together. In this work, we have applied thermal desorption spectroscopy (TDS) to study dimethyl methylophosphate (DMMP, sarin analogue) adsorption on zinc phthalocyanine (ZnPc), aiming to achieve the quantification of the sensing mechanism. Furthermore, we utilize a novel approach to TDS that involves quantum chemistry calculations for the determination of desorption activation energies. As a result, we have provided a comprehensive description of DMMP desorption processes from ZnPc, which is the basis for successful future applications of sarin ZnPc-based sensors. Finally, we have verified the sensing capability of the studied material at room temperature using impedance spectroscopy and took the final steps towards demonstrating ZnPc as a promising sarin sensor candidate.

Structural features of 18R-type long-period stacking ordered phase in Mg85Zn6Y9 alloy and the Ni doping effect on its hydrogen storage properties

Magnesium-based alloys with 18R-type long-period stacking ordered (LPSO) structures have attracted wide attention for structural and functional applications. To understand hydrogen storage properties of 18R phase, the Mg85Zn6Y9 alloy with 94 wt.% of 18R-type LPSO phase is prepared in this work. The 18R phase has a layered structure where Y-Zn-Mg and Mg layers alternately stack along the c-axis. In the Y-Zn-Mg layers, Y, Zn and partial Mg sites are co-occupied by Y and Mg, Zn and Mg, and Mg and Zn/Y atoms, respectively. Thus the 18R phase is easily decomposed into α-MgH2, γ-MgH2, YH2, YH3, C14-type Laves phase MgZn2 and minor CsCl-type Y(Mg,Zn) during ball milling under hydrogen atmosphere. After further hydrogen absorption-desorption cycling, Y(Mg,Zn) disappears gradually and C14 phase transforms into C15-type Laves phase. By contrast, the Mg85Zn6Y9 alloy has better hydrogen storage kinetics and cycle durability than pure Mg because of the catalytic effect of YH2/YH3 on hydrogen absorption-desorption and inhibition role of Laves phase in Mg crystallite growth. Moreover, the introduction of Ni into Mg85Zn6Y9 sample leads to a further decrease in activation energy of hydrogen desorption from 106.39 to 96.78 kJ mol−1 due to the formation of Mg2Ni. This work not only provides new insights into structural features and hydrogen storage characteristics of 18R phase but offers an effective method for improving hydrogen storage properties.

Dual-cation K2TaF7 catalyst improves high-capacity hydrogen storage behavior of MgH2

MgH2 has been extensively regarded as a low-cost hydrogen storage material with high gravimetric hydrogen capacity of approximately 7.6 wt%. However, the hydrogen release and absorption kinetics in MgH2 still needs further improving. For the first time, the catalytic impacts of a new dual-cation metal fluoride K2TaF7 upon the hydrogen storage characteristics of MgH2 have been investigated in this work. With only 1 wt% K2TaF7 dopant, the initial dehydrogenation temperature of MgH2 was lowered by about 130 °C, releasing more than 7.3 wt% hydrogen totally. The desorption activation energy of MgH2 + 1 wt% K2TaF7 composite was decreased to 107.2 ± 1.2 kJ mol−1. Besides, at 190 °C, the dehydrogenated MgH2 + 1 wt% K2TaF7 sample could absorb 6.56 wt% H2, while pristine MgH2 re-absorbed only 3.45 wt% H2. Further studies revealed that K2TaF7 could react with MgH2 during dehydrogenation and produce symbiotic hydrides KMgH3 and TaH0.8, which could play the role of hydrogen pumps during hydrogen release and uptake. The cooperative catalysis between the hydrogen pump effect and the active interface in the multi-hydride area significantly enhanced the reversible hydrogen storage in the MgH2+1 wt% K2TaF7 composite. This study provides new thinking for novel catalysts to elevate the hydrogen storage performance of MgH2.

Michaelis–Menten kinetics during chemical etching of germanium

The chemical etching of germanium in Br2 environment is investigated theoretically. The steady-state etching rate is described by the Michaelis-Menten equation. It shown that Michaelis constant is the ratio of desorption rate constant to reaction rate constant. The activation energies of elementary processes are evaluated using the transition state theory. It is found that the activation energy of Ge(s) + Br2(g) → GeBr2(a) reaction is equal to (1.168±0.173) eV, and the desorption activation energy of GeBr2 molecules is equal to (1.404±0.077) eV. The Michaelis constant depends on temperature because the reaction activation energy differs from the desorption activation energy. Surface passivation by GeBr radicals is not observed under the investigated experimental conditions.

Boosting the hydrogen storage performance of magnesium hydride with metal organic framework-derived Cobalt@Nickel oxide bimetallic catalyst

In this study, a MOF-derived bimetallic [email protected] catalyst was synthesized and doped into MgH2 to improve the hydrogen desorption and resorption kinetics. The [email protected] catalyst decreased the onset dehydrogenation temperature of MgH2 by 160 °C, compared with un-doped MgH2. The MgH2 + 9% (mass) [email protected] composite released 6.6% (mass) hydrogen in 350 s at 315 °C and uptook 5.4% (mass) hydrogen in 500 s at 165 °C, showing greatly accelerated de/rehydrogenation rates. Besides, the desorption activation energy of MgH2 + 9% (mass) [email protected] was decreased to (93.8 ± 8.4) kJ·mol−1. Noteworthy, symbiotic Mg2NiH4/Mg2CoH5 clusters were in-situ formed from bimetallic precursors and inlaid on MgH2 surface, which are considered as “multi-step hydrogen pumps”, and provides surface pathways for hydrogen absorption. Meanwhile, the introduced Mg2NiH4/Mg2CoH5 interfaces could provide numerous low energy barrier H diffusion channels, therefore accelerating the hydrogen release and uptake. This research proposes new insights to design high-efficiency bimetallic catalyst for MgH2 hydrogen storage.

Improved hydrogen storage performance of Sm-Mg composites by adding nano-graphite

Sm5Mg41 + x wt% nano-graphite (NG) (x = 0, 2, 4, 8, 12) composites are synthesized via ball-milling. The influences of NG content on microstructure and hydrogen storage properties of the composites are researched systematically. The composites consist of Mg, Sm5Mg41, SmMg3, and NG. Nano scale Sm3H7 and MgH2 phases are observed after the hydrogen absorbing, and the newly formed Mg phase and the remaining Sm3H7 phase appear after hydrogen desorbing. NG is embedded in the surface of the composites in the form of nanosheets. Nanocrystalline Mg and some microscopic defects, including twin crystal, grain boundaries, and dislocations can be observed in the dehydrogenated sample. Such microscopic defects and nanocrystalline boundaries can reduce the total potential barrier needed to overcome during the hydrogen absorption/desorption reactions and thus the hydrogen storage kinetics of the alloy are improved. For the composites with x = 2, 4, 8 and 12, the activation energies of hydrogen desorption are 132.08, 128.06, 112.90, and 112.35 kJ/mol H2, respectively. The enthalpy changes for the hydrogen absorption are evaluated to be − 79.18, − 78.09, − 76.30, − 76.10 kJ/mol H2, indicating that the addition of NG had no obvious effect on the thermodynamic properties of the composites.

A comparative study of hydrogen storage properties of AZ31 and AZ91 magnesium alloys processed by different methods

We studied the hydrogen storage properties of commercial AZ31 and AZ91 magnesium alloys with refined microstructure. Various processing techniques, such as equal channel angular pressing (ECAP) and high energy ball milling (HEBM), were utilized to modify the microstructure and phase composition of the alloys. X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical digital microscopy (ODM) were utilized to characterise the microstructure and phase transformations during the hydrogen absorption/desorption processes. The isothermal kinetics are measured by a Sieverts’-type apparatus at the temperature of 350 ℃. In the ECAP process, the AZ31 alloy had a slightly higher storage capacity and faster absorption kinetics, absorbing 6.0 wt% (6.6 wt% - maximum) of hydrogen in less than 12 min. In the HEBM process, AZ91 absorbed 6.5 wt% of hydrogen and desorbed it in 347 ± 13 s, a faster rate than AZ31. The pressure–composition isotherms of all studied alloys at a temperature of 300 °C were determined. The processed alloys exhibited no pressure hysteresis. The microstructure of bulk samples and the morphology of prepared powders were shown to affect their hydrogenation behaviour. The activation energies for hydrogen desorption were 119 ± 2 kJ/mol for AZ31 alloy processed by ECAP and 128 ± 3 kJ/mol for AZ91 alloy processed by HEBM, which are significantly lower than the activation energy values of pure Mg hydride.

Kinetics of oxygen sorption-desorption processes in manganites of La0.7Sr0.3Mn0.9Fe0.1O3-δ composition

Based on the data of thermogravimetric analysis the values of the oxygen index (3-δ) in the manganite of the La0.7Sr0.3Mn0.9Fe0.1O3-δ composition, obtained by solid-phase reaction technique, have been calculated. The analysis of oxygen sorption-desorption curves showed that the processes of oxygen release and absorption at pO2 = 10 Pa and pO2 = 400 Pa are not reversible. The minima of the derivative dδ/dt = f (T) corresponding to the maxima of the oxygen extraction rate indicate the complex character of changes in the oxygen desorption rate from manganite. The decrease in the heating and cooling rate from 6.6 K/min to 2.6 K/min resulted in a significant change in the value ∆δ, indicating the dependence of anion mobility on the oxygen concentration in the magnet structure. It has been revealed that in the La0.7Sr0.3Mn0.9Fe0.1O3-δ manganite the oxygen desorption kinetics is well described by the exponential dependence on the Kramers model, which implies no return of desorbed oxygen to the sample. This model indicates the non-stationarity of the diffusion flux through the barrier during desorption of oxygen from samples. The calculation of the activation energy of oxygen desorption by the Merzhanov method at various partial pressures of oxygen has shown that at the initial stage of oxygen extraction from La0.7Sr0.3Mn0.9Fe0.1O3-δ, the activation energy of oxygen desorption has a minimum value (Еа = 103.7 kJ/mol at δ = 0.005) and as the concentration of oxygen vacancies increases, it rises reaching saturation (Еа = 134.3 kJ/mol at δ = 0.06). It is assumed that with an increase in the concentration of oxygen vacancies, an interaction occurs between them, followed by the processes of their ordering with the formation of associates.

Structural transitions on Si(1 1 1) surface during Sn adsorption, electromigration, and desorption studied by in situ UHV REM

Using in situ ultrahigh vacuum reflection electron microscopy, we have studied structural transitions on the Si(111) surface induced by Sn deposition up to 2 ML coverage (1 ML = 7.8∙1014 cm−2) and by Sn desorption at substrate temperatures T = 200–860 °C. We have shown that Si–Sn intermixing in the adsorption layer during Sn deposition onto the Si(111)-(7 × 7) surface at T > 650 °C leads to the shift of the monatomic steps in the step-up direction, and there is formed a mosaic (√3×√3)-Sn phase. The electromigration of Sn adatoms induced by DC resistive heating has been shown to redistribute adsorbed Sn layer and to cause local (√3×√3)-Sn ⇔ “1 × 1”-Sn structural transitions on the surface. We have estimated the lower bound of the Sn adatom positive effective charge on the Si(111) surface qeffSn ≥ 0.001∙e. During AC annealing, the rate of desorption-induced “1 × 1”-Sn domain area shrinkage has been measured as a function of substrate temperature, and the activation energy of Sn adatom desorption has been estimated to be 2.5 ± 0.1 eV.

Desorption activation energy of hydrogen from the Si (111)1x1: H surface studied by optical sum frequency generation and second harmonic generation

The desorption kinetics of hydrogen from the H-Si (111)1 × 1 surface prepared by molecular hydrogen exposure has been studied by combining optical sum frequency generation (SFG) for higher coverage and second harmonic generation (SHG) for lower coverage at several sample temperatures from 711 K to 770 K. The hydrogen desorption activation energy was found as Ed = 60.1 ± 8.8 kcal/mol (2.60 ± 0.38 eV) for the second order desorption for the coverage above 0.44 ML. For the first order desorption at the coverage below 0.18 ML the desorption activation energy was found as Ed= 32.6 ± 8.1 kcal/mol (1.41±0.35 eV).

Bi-amine functionalized mesostructured silica nanospheres for enhanced CO2 adsorption performance and fast desorption kinetics

A novel solid bi-amine adsorbent was synthesized by simultaneously impregnating pentaethylenehexamine (PEHA) and aminoethylethanolamine (AEEA) on the surfaces of mesoporous MCM–41 nanospheres. AEEA and PEHA had a synergistic effect during the CO2 adsorption of the bi-amine adsorbent and the highest CO2 adsorption capacity was 4.03 mmol·g−1. The bi-amine adsorbent exhibited the favorable recyclability because its saturated CO2 adsorption capacity decreased by 6.20 % after the initial eight adsorption/desorption cycles while by only 2.23 % in the following seven cycles. The adsorption activation energy and the desorption activation energy were determined to be 12.53 and 16.81 kJ·mol−1, respectively. The low value of the desorption activation energy suggested an inconsiderable energy requirement in the multicycles of the adsorbent. The characterization results indicated that hydrogen bonds were formed between the hydrogen atom in hydroxyl groups of AEEA and the oxygen atom in carbonyl groups of the carbamate. The synergistic effect between AEEA and PEHA was unveiled on the CO2 adsorption of the bi-amine adsorbent. The formed hydrogen bonds facilitated the release of protons from carbamic acids, enhanced the stability of the produced carbamate anions, and thus boosted the CO2 adsorption performance.

Influence of Nanosized CoTiO3 Synthesized via a Solid-State Method on the Hydrogen Storage Behavior of MgH2.

Magnesium hydride (MgH2) has received outstanding attention as a safe and efficient material to store hydrogen because of its 7.6 wt.% hydrogen content and excellent reversibility. Nevertheless, the application of MgH2 is obstructed by its unfavorable thermodynamic stability and sluggish sorption kinetic. To overcome these drawbacks, ball milling MgH2 is vital in reducing the particle size that contribute to the reduction of the decomposition temperature. However, the milling process would become inefficient in reducing particle sizes when equilibrium between cold-welding and fracturing is achieved. Therefore, to further ameliorate the performance of MgH2, nanosized cobalt titanate (CoTiO3) has been synthesized using a solid-state method and was introduced to the MgH2 system. The different weight percentages of CoTiO3 were doped to the MgH2 system, and their catalytic function on the performance of MgH2 was scrutinized in this study. The MgH2 + 10 wt.% CoTiO3 composite presents the most outstanding performance, where the initial decomposition temperature of MgH2 can be downshifted to 275 °C. Moreover, the MgH2 + 10 wt.% CoTiO3 absorbed 6.4 wt.% H2 at low temperature (200 °C) in only 10 min and rapidly releases 2.3 wt.% H2 in the first 10 min, demonstrating a 23-times-faster desorption rate than as-milled MgH2 at 300 °C. The desorption activation energy of the 10 wt.% CoTiO3-doped MgH2 sample was dramatically lowered by 30.4 kJ/mol compared to undoped MgH2. The enhanced performance of the MgH2–CoTiO3 system is believed to be due to the in situ formation of MgTiO3, CoMg2, CoTi2, and MgO during the heating process, which offer a notable impact on the behavior of MgH2.