Novel ultralow-temperature sodium borohydride hydrogen production catalyst

Abstract

The invention discloses a novel ultralow-temperature sodium borohydride hydrogen production catalyst and application thereof. The catalyst is composed of five metal elements of Co, Ni, Fe, Mo and W, the molar ratio range is 1: (0.8-1.2): (0.3-0.7): (0.1-0.4): (0.05-0.2), and the preferable ratio is 1: 1: 0.5: 0.2: 0.1. The catalyst is loaded on a carbon cloth, graphene oxide or foamed nickel carrier in the form of nanoparticles with the particle size of 5-50 nm, the specific surface area is larger than or equal to 50 m < 2 > / g, and the catalyst is prepared through a pulse electroplating method (the current density is 0.12 A / cm < 2 >, and the duty ratio is 70%). In a NaBH4 low-temperature alcoholysis system with the pH value of 10-13 and the temperature of-40 DEG C to 0 DEG C, the catalyst has the remarkable performance that the hydrogen production rate reaches 30 mL * min <-1 > * cm <-2 > at the temperature of-10 DEG C to 0 DEG C, and the catalyst is suitable for an emergency power supply; at-20 DEG C to-10 DEG C, the temperature is 20 mL. Min <-1 >. Cm <-2 >, and unmanned monitoring equipment is adapted; when the temperature is-30 DEG C to-20 DEG C, energy supply is met by 10mL. Min <-1 >. Cm <- The temperature of-40 DEG C to-30 DEG C is still kept at 5mL. Min <-1 >. Cm <-2 >, and equipment in an extreme environment is supported. After 100 cycles, the activity retention rate exceeds 90%, the service life of M-10 and M-0 models can reach 5000 hours, the bottleneck of temperature adaptation limit and durability of the existing low-temperature catalyst is broken through, and the catalyst has remarkable technical progress and industrial application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production, and specifically relates to a sodium borohydride (NaBH4) alcoholysis hydrogen production catalyst applicable to ultra-low temperature environments (-40°C to 0°C), its preparation method and application. Background Art

[0002] As a clean energy source, hydrogen has the advantages of high energy density and zero emissions, and is widely used in fields such as fuel cells, chemical synthesis, and energy storage. Traditional hydrogen production methods such as steam reforming and electrolysis of water are limited by the low-temperature activity, insufficient stability of the catalyst, and application limitations, and it is difficult to meet the hydrogen supply demand in extreme environments. Sodium borohydride (NaBH4), as an efficient hydrogen storage material, has received extensive attention due to its high hydrogen storage density and safety. However, the existing sodium borohydride hydrogen production technology does not have a corresponding low-temperature catalyst. The activity of noble metal catalysts (such as Pt, Ru) decreases at low temperatures (<0°C), while non-noble metal catalysts (such as Co, Ni-based) have slow reaction kinetics. The existing catalysts are prone to deactivation in a highly alkaline environment (pH>10) after long-term use, and the cycle life is insufficient. The lack of catalysts suitable for extremely low temperatures (such as -40°C) makes it difficult to meet the special needs of low-temperature power supply such as emergency power supplies.

[0003] In view of the above problems, the present invention proposes a novel catalyst Co-Ni-Fe-Mo-W based on five elements of Co, Ni, Fe, Mo, and W, which utilizes the synergistic effect of the elements to enhance the low-temperature catalytic activity, while enhancing the stability and anti-poisoning properties of the catalyst to meet the hydrogen energy application requirements in extreme environments. Summary of the Invention

[0004] The purpose of the present invention is to provide a novel ultra-low temperature sodium borohydride hydrogen production catalyst to solve the problems proposed in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] Composition and Structure of the Catalyst

[0007] Metal molar ratio: Co:Ni:Fe:Mo:W = 1:(0.8 - 1.2):(0.3 - 0.7):(0.1 - 0.4):(0.05 - 0.2), preferably 1:1:0.5:0.2:0.1.

[0008] Morphology: Nanoparticles (5 - 50 nm), or supported on carbon cloth, graphene oxide (GO), nickel foam carrier, specific surface area ≥ 50m 2 / g.

[0009] Catalytic synergy mechanism: Fe enhances alloy stability; Mo / W promotes electron transfer and improves low-temperature catalytic activity; Co / Ni provides active centers and optimizes the adsorption-dissociation mechanism.

[0010] Catalyst preparation method

[0011] Support pretreatment: The carbon cloth is soaked in nitric acid (concentration 5 mol / L, 2 h) and then ultrasonically cleaned.

[0012] Pulse electroplating:

[0013] Electrolyte: CoSO4 (0.1 M), NiSO4 (0.1 M), FeSO4 (0.05 M), Na2MoO4 (0.02 M), Na2WO4 (0.01 M); current density 0.12 A / cm 2 , duty cycle 70%, electroplating time 30 min;

[0014] Post-treatment: Anneal at 600 °C for 1 h in a nitrogen atmosphere to obtain the CoNiFeMoW / carbon cloth catalyst.

[0015] Catalyst application

[0016] The catalyst is used in the alkaline NaBH4 alcoholysis hydrogen production system (pH 10 - 13), at a temperature of -40 °C to 0 °C. Although the reaction rate decreases at low temperatures, it can still maintain a certain reaction activity. Hydrogen production for power supply can be applied to:

[0017] The power supply problem in the off-grid state in Northeast China. Compared with transition metal oxide catalysts, the production cost is relatively low.

[0018] The problem of ensuring both low temperature and power supply during cold chain logistics transportation. This catalyst can well solve this problem.

[0019] Unattended mine equipment: The mine unattended system needs to ensure stable power supply in the off-grid state. Co, Ni, Fe, etc. can be used as catalysts to react with sodium borohydride to produce hydrogen as fuel, continuously supplying hydrogen to promote the mining industry to be safer, more efficient and intelligent.

[0020] When operating in the field, this catalyst is convenient and portable. It can react with sodium borohydride to serve as a mobile power source, continuously providing electricity and reducing the impact of power limitations. For example, when the power facilities in the surrounding areas were damaged due to the wildfires in Los Angeles, the hydrogen fuel cell could be used as a mobile power source to provide stable power support for the fire command center, temporary shelters, rescue equipment, etc. Installing a fuel cell power generation device on a fire truck makes the fire truck have the characteristics of zero emissions, low noise, and high efficiency. It can supply power to on-site lighting equipment and communication equipment, better perform tasks, ensure the smooth progress of rescue work, and can also provide power for equipment such as drones to improve rescue efficiency.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] High-efficiency hydrogen production at low temperature:

[0023] Under the conditions of -40°C to 0°C, the hydrogen production rate (HGR) is 5 - 30 mL·min-1·cm-2, and the lifespan is 168 - 5000 hours.

[0024] Long lifespan and stability:

[0025] After 100 cycles of use, the catalyst activity retention rate > 90%.

[0026] Anti-poisoning and corrosion resistance:

[0027] The elements Mo and W optimize the electronic structure, improve the antioxidant and anti-poisoning abilities of the catalyst, and are applicable to the alkaline NaBH4 system (pH 10 - 13).

[0028] Low-cost industrial applicability:

[0029] The production cost is only 20% of that of noble metal catalysts, which can meet the requirements of large-scale production.

[0030] In summary, the present invention can efficiently and stably catalyze the alcoholysis of sodium borohydride (NaBH4) to produce hydrogen in a low-temperature environment as low as -40°C, expanding the application of sodium borohydride hydrogen production in multiple scenarios. Description of the Drawings

[0031] Appendix Figure 1 It is the hydrogen production rate of the Co-Ni-Fe-Mo-W catalyst tested at -20°C, respectively representing the hydrogen production contribution of each catalyst element to the catalyst. Specific Embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0033] Embodiment 1

[0034] Using M-10 type catalyst, NaBH4 solution with pH = 12, reaction temperature -10°C, HGR 30 mL·min -1 ·cm -2 , with a service life of 3600 - 5000 hours.

[0035] Example 2

[0036] Using M-20 type catalyst, NaBH4 solution with pH = 12.5, reaction temperature: -20°C, HGR 20 mL·min -1 ·cm -2 , with a service life of 3600 hours.

[0037] Example 3

[0038] Using M-30 type catalyst, NaBH4 solution with pH = 11.5 (concentration 1 mol / L), reaction temperature -30°C, HGR 10 mL·min -1 ·cm -2 , which can last for 168 hours.

[0039] Example 4

[0040] Using M-40 type catalyst, NaBH4 solution with pH = 12, reaction temperature -40°C, HGR 5 mL·min -1 ·cm -2 , which can last for 24 - 168 hours.

[0041] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A novel ultra-low temperature sodium borohydride hydrogen production catalyst, comprising: The novel low-temperature catalyst comprises five elements: Co, Ni, Fe, Mo, and W, and the metal molar ratio of each element is: Co:Ni:Fe:Mo:W=1:(0.8-1.2):(0.3-0.7):(0.1-0.4):(0.05-0.2); The catalyst is in the form of nanoparticles with a particle size between 5 and 50 nm, supported on carbon cloth, graphene oxide (GO), or nickel foam carrier, and has a specific surface area of ​​≥50 m 2 / g. The preparation method of the novel ultra-low temperature catalyst is a pulse electroplating method, using a current density of 0.12A / cm 2 , duty cycle 70%.

2. The catalyst according to claim 1, characterized in that: The novel low-temperature catalyst is applied to a NaBH4 low-temperature alcoholysis hydrogen production system, the pH value of which is 10–13 and the reaction temperature ranges from -40°C to 0°C.

3. The catalyst according to claim 1, characterized in that: In different temperature ranges, the hydrogen production method has the following hydrogen production rates and application scenarios: At -10℃, the hydrogen production rate (HGR) is 30mL·min -1 cm -2 ; At -20℃, HGR is 20mL·min -1 cm -2 ; At -30℃, HGR is 10mL·min -1 cm -2 ; At -40℃, HGR is 5mL·min -1 cm -2 .

4. The catalyst according to claim 1, characterized in that: The novel low-temperature catalyst has the following performance: after 100 cycles of use, the catalyst activity retention rate is >90%.

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