Catalysts

Applied

Synthesis Process

Test Parameter

Observations

CH₃OH conversion

%

Ref.

Achievements

Limitations

Ce, La, Sm, Y, and Gb promoted Cu/Zn-Al-Htlc

In-situ synthesis for catalyst precursor and wet impregnation for doping

250˚C

Ce/Cu/ZnAl hydrotalcite catalyst exhibited high activity, methanol conversion of 100% and low CO concentration

La/Cu/ZnAl and Y/Cu/ZnAl catalysts have inferior performances because of smaller surface area of copper and higher reduction temperatures

100

[127]

Cu supported ZnAl-Htlc/

γ-Al₂O₃

In-situ synthesis for catalyst precursor and wet impregnation for Cu support

300˚C

Cu incorporation enhanced reducibility and catalytic activity

Higher Cu incorporation (>10%) decreased methanol conversion

99.98

[128]

Cu, Ni, Zn, and Albased hydrotalcite

Co-precipitation followed by calcination at 400˚C for 1h

220˚C - 260˚C

The developed Cu_0.75Al_0.25catalyst showed better activity, active metal dispersion and methanol conversion than the benchmark catalyst

At higher operational temperatures CO concentration increased considerably

76

[129]

CuO/ZnO/

Al₂O₃ and K-Htlc

Calcination of parched Htlc at 400˚C for 4 h then dry impregnation for K loading

230˚C

Catalyst with K-Htlc absorbent was able to convert CH₃OH at lower temperatures and the product gas contained 99.16 % H₂ and only 0.39% CO

High regeneration temperature of the absorbent caused sintering of the catalyst

-

[130]

Cu/Zn-Al

Hydrotalcite

Co-precipitation for Zn-Al Htlc and wet impregnation for Cu incorporation

200˚C - 350˚C

Catalyst with 10% Cu performed 99.78% methanol conversion

Compromise between reducibility dispersion of Cu species has to be made for good catalytic performance

and low CO generation

99.78

[131]

Cu/Zn-Al-Htlc

Co-precipitation inside microemulsion

droplets and then calcination in the air for 3 h at 330˚C

260˚C

Catalyst developed by micro-emulsion technique exhibited improved catalytic performances during CH₃OH steam reforming

Micro-emulsion produced catalyst with poor intrinsic activity

69

[132]

PdZn-Htlc,

Pd₂Ga-Htlc, and

Pd-Htlc

Co-precipitation for Htlc and reductive decomposition for intermetallic support incorporation

200˚C - 300˚C

Intermetallic nanoparticle supported Htlc catalyst exhibited improved catalytic activity and selectivity. Where Pd₂Ga-Htlc catalyst showed the best

result

The activity of the intermetallic Htlc catalyst was less than Cu/ZnOHtlc catalyst

9.5

[133]