KR-102965298-B1 - Method for manufacturing reduced graphene oxide catalyst using dual pulse laser and reduced graphene oxide catalyst prepared thereby

Abstract

The present invention provides a method for manufacturing a reduced graphene oxide catalyst using a dual pulse laser, comprising: a first step of preparing a mixed solution comprising a graphene oxide solution, a metal precursor solution, and a reducing agent; a second step of placing the mixed solution into a vial and irradiating it with a dual pulse laser; and a third step of centrifuging the solution in the vial after the second step to produce a reduced graphene oxide (rGO) catalyst having a metal or metal hydroxide formed on its surface; wherein, in the second step, the dual pulse laser is characterized by simultaneously irradiating a first laser having a wavelength of 250 to 400 nm and a second laser having a wavelength of 750 to 1200 nm to shorten the manufacturing time of the reduced graphene oxide catalyst. The method for preparing a reduced graphene oxide catalyst according to the present invention utilizes a dual-pulse laser, allowing for the simple synthesis of the catalyst without undergoing multiple processes. Furthermore, it is environmentally friendly as it does not use chemicals or emit carbon dioxide during material synthesis, and process costs can be reduced by using graphene, which has high electrical conductivity, as a catalyst auxiliary material. Accordingly, the reduced graphene oxide catalyst produced possesses excellent OER catalytic activity by efficiently enhancing electron hopping through a heterointerface structure and promoting mass and electron transfer, making it suitable for use in hydrogen energy applications.

Inventors

• 최명룡
• 이예령
• 민아름
• 문철주
• 띠따기리 자야라만

Assignees

• 경상국립대학교산학협력단

Dates

Publication Date

20260513

Application Date

20240417

Claims (5)

1. A first step of preparing a mixed solution comprising a graphene oxide solution, a non-precious metal precursor solution, and a reducing agent; A second step of simultaneously irradiating the above mixed solution with a first laser having a wavelength of 250 to 400 nm and a second laser having a wavelength of 750 to 1200 nm using a dual pulse laser; and A third step of preparing a reduced graphene oxide (rGO) catalyst in which a non-precious metal or non-precious metal hydroxide is formed on the surface by centrifuging the solution after the second step; wherein In the second step above, the graphene oxide is reduced by the dual-pulse laser irradiation to form reduced graphene oxide (rGO), and simultaneously, a non-precious metal or non-precious metal hydroxide is bonded to the rGO to form an rGO catalyst with a heterointerface structure. A method for preparing a reduced graphene oxide catalyst having a heterointerface structure formed with a non-precious metal or a non-precious metal hydroxide.
2. In Article 1, In the second step above, A method for producing a reduced graphene oxide catalyst having a heterogeneous interface structure formed with a non-precious metal or non-precious metal hydroxide, characterized in that the first laser and the second laser are irradiated horizontally.
3. In Article 1, The concentration of the above non-precious metal precursor solution is, A method for preparing a reduced graphene oxide catalyst characterized by having a heterostructure formed with a non-precious metal or non-precious metal hydroxide, wherein the composition is 2.5 to 20 mM.
4. In Article 1, The above-mentioned reduced graphene oxide catalyst is, A method for preparing a reduced graphene oxide catalyst characterized by catalyzing an oxygen evolution reaction (OER), having a heterostructure formed with a non-precious metal or non-precious metal hydroxide.
5. A reduced graphene oxide catalyst characterized by being manufactured according to any one of claims 1 to 4.

Description

Method for manufacturing reduced graphene oxide catalyst using dual pulse laser and reduced graphene oxide catalyst prepared thereby The present invention relates to a method for preparing a reduced graphene oxide catalyst using a dual-pulse laser and a reduced graphene oxide catalyst prepared according to the same. The development of new and renewable energy sources capable of simultaneously mitigating the energy crisis caused by fossil fuel depletion and global warming resulting from various environmental pollutants is receiving significant scientific and industrial attention. Various studies have been conducted on eco-friendly and inexhaustible renewable energy sources to replace fossil fuels, and among these, hydrogen energy is a representative energy carrier. Hydrogen reacts with oxygen in the air to produce only water, without generating other pollutants. The energy density per unit mass of hydrogen is 142 kJ/g, which is four to three times higher than that of gasoline and natural gas. Although there are various methods for producing hydrogen, the most popular method currently is extracting it from fossil fuels. However, since this method causes environmental problems, one of the eco-friendly hydrogen production methods is water electrolysis. Water electrolysis is carried out in polymer electrolyte membranes or alkaline water electrolyzers, but there is a problem with low energy efficiency. This is mainly because the oxygen evolution reaction (OER) slows down at the anode of the electrolyzer due to 4-electron OER transport and insufficient performance of OER catalysts. Accordingly, in order to solve the above problem by producing highly active OER catalysts, a lot of research is being conducted on low-cost electrode catalyst materials such as metal sulfides, nitrides, carbides, and phosphides. Furthermore, heterointerfaces are being studied as an effective strategy to overcome the limitations of electrochemical activity and enhance the intrinsic activity of catalysts. By facilitating the generation of active sites and the control of electronic structures through heterostructure assembly, synergistic effects of multi-component materials are utilized. Among these, graphene-based heterostructures can be used in various electrochemical energy conversion applications due to their unique properties, including electron transport and the Hall effect. Since the oxidation of graphene reduces conductivity, it is necessary to reduce it to restore sp2 hybridization. Graphene oxide (GO) is reduced through chemical, ultrasonic dissolution, microwave, thermal, photocatalytic, and composite processes to synthesize reduced graphene oxide (rGO). These processes require maintaining the unique reactions of graphene sp2 hybridization, which are essential for electrochemical applications. Meanwhile, transition metals operate similarly to rGO due to their excellent electrochemical behavior and stability and are widely used in OER; however, there are limitations in that OER kinetics are restricted due to low conductivity and intrinsic behavior depending on the position of the transition metal ions (hindering charge transport and desorption activities, thereby ultimately hindering oxygen generation). Accordingly, the inventors developed a method for preparing a reduced graphene oxide catalyst using a dual pulsed laser assisted synthesis (PLAS) technique to combine reduced graphene oxide with a transition metal for use as a catalyst, and a reduced graphene oxide catalyst prepared thereby, thereby completing the present invention. Figure 1 shows the formation mechanism of a reduced graphene oxide catalyst prepared according to one embodiment of the present invention. Figure 2 shows the XRD and Raman spectra of an α-Co(OH) 2 /rGO nanosheet according to one embodiment of the present invention. Figure 3 shows the UV-vis spectra of pure α-Co(OH) 2 /rGO, rGO, and bare GO samples prepared with a single laser pulse. Figure 4 is the XPS analysis result of an α-Co(OH) 2 /rGO nanosheet according to one embodiment. Figure 5 is a FESEM-EDS mapping image for the elemental and lattice structure analysis of α-Co(OH) 2 /rGO nanosheets according to one embodiment of the present invention. Figure 6 is an XPS graph of a Ni/rGO nanosheet according to one embodiment. Figure 7 is a TEM image of a Ni/rGO nanosheet according to one embodiment. Figure 8 shows the UV-vis graph and Raman graph of graphene synthesized according to an embodiment (dual laser) and a comparative example (single laser) of the present invention. FIG. 9 is a schematic diagram showing the arrangement structure of a dual pulse laser according to an embodiment of the present invention. Figure 10 is a graph showing the OER performance of an α-Co(OH) 2 /rGO nanosheet according to one embodiment of the present invention. Figure 11 shows the OER mechanical pathway and EC-Raman spectrum of an α-Co(OH) 2 /rGO nanosheet according to one embodiment of the present invention. Figure 12 is an