Nickel-based catalyst for hydrogen production by ethanol steam reforming and preparation method thereof

Abstract

The invention discloses a nickel-based catalyst for hydrogen production by ethanol steam reforming and a preparation method thereof. The catalyst is made by taking nanoporous silicon dioxide aerogel as a catalyst carrier, a metal elementary substance nickel nanowire as an active component, and nano-particles of MgO or CaO or ZrO2 or TiO2 or CeO2 or compound nano-particles thereof as an adjuvant. The preparation method comprises the following steps: preparing a sol from silanolate, an alcohol solvent, nickel nitrate or magnesium nitrate or calcium nitrate or zirconium nitrate or cerous nitrate or complex nitrate thereof and an acidic catalyst at certain proportions; forming a wet gel complex, and then performing supercritical fluid drying. The catalyst has strong catalytic activity and selectivity for the hydrogen production by the ethanol steam reforming, has higher hydrogen yield and stronger CO2 selectivity at a lower temperature, and limits the selectivity of byproducts CH4 and CO at a lower level. Meanwhile, the preparation method has simple process, low cost and certain mechanical strength.

Description

technical field [0001] The invention belongs to the technical field of catalyst materials for hydrogen production by ethanol steam reforming of liquid fuel used in fuel cells, and relates to a nickel-based catalyst for hydrogen production by ethanol steam reforming and a preparation method thereof, in particular to a silicon dioxide gas The invention relates to a nickel-based nano-catalyst with a gel as a carrier and a preparation method thereof. Background technique [0002] Fuel cells directly and efficiently convert the chemical energy stored in fuel and oxidant into electrical energy. High-purity, non-toxic hydrogen is an ideal fuel for fuel cells. Currently, liquid fuel reforming is a better way to produce hydrogen. [0003] Ethanol is a renewable resource, non-toxic, and does not contain sulfur that is likely to poison the platinum electrodes of fuel cells. It is an environmentally friendly fuel suitable for hydrogen production. Ethanol steam reforming is an importa...

AI Technical Summary

Problems solved by technology

This type of catalyst has high ethanol conversion rate and hydrogen production effect (such as Ni / Al 2 o 3 The conversion rate of ethanol can reach 91% above 500°C, and the reaction gas contains 70% H 2 ), but due to the catalyst support Al 2 o 3 The acidity of the catalyst leads to serious carbon deposition and poor stability

Furthermore, CH on Ni-based catalysts 4 and the formation of CO is relatively large, CH 4 Competing for hydrogen atoms, CO poisons the fuel cell's Pt electrodes, both undesired by-products

While in cobalt-based catalysts (such as Co / Al 2 o 3 , Co / SiO 2 , Co / MgO and Co / SrTiO 3 ), with higher selectivity (such as Co / ZnO, the catalyst can completely convert ethanol at a lower temperature (350° C.), and the selectivity is very high. After the reaction, the CH4 content in the gas is lower than 3%. CO was not detected), but is easily inactivated, and its problem is poor stability

[0007] In addition, impregnation and co-precipitation methods are currently used to prepare non-precious metal catalysts. Although the preparation process is simple, it is difficult to obtain catalysts with high specific surface area, high dispersion and uniform dispersion, resulting in catalytic activity for the steam reforming reaction of ethanol. to be further improved

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