Table 1 Various type of Pt bimetallic, tertiary, and quaternary metal alloys and their performance

PtRu

ND

Reduction

Pt–Ru (25:1) catalyst demonstrated highest electrocatalytic activity, higher resistance to CO, and better long-term stability compared to Pt–Ru (3:1), Pt–Ru (1:1), and Pt.

Addition of more Ru could decrease the catalyst activities.

CO species removed from catalyst surface by the OH at high potentials.

Methanol electrooxidation activities also effected by of scan rate, temperature, methanol, and acid concentration.

[41]

PtRh

5.4 nm

Reduction

Synthesis of PtRh nanosponge (NS) with 3D porous structure with interconnected pores.

Much more stable catalyst in methanol oxidation as proved by CA measurement.

Greatly improved MOR activity as compared to Pt nanoparticles and commercial Pt/C catalyst.

PtRh showed higher ECSA value than Pt nanoparticles.

[192]

PtAu

3 nm

Electrodeposition

From morphologies study Pt and Au, they are in spherical and dendrite shape.

PtAu exhibited remarkably enhanced MOR (3.947 mA cm⁻²)

The catalytic in MOR was 2.65 times higher that of commercial Pt/C (1.487 mA cm⁻²) which can be related with the electronic structure of Pt when Au surface was modified by fewer Pt nanoparticles.

Much improved in poisoning tolerance.

[72]

PtSn

5.2 nm

Impregnation

The potential of PtSn/C-PANI was tested in a DMFC cell which showed lower methanol crossover by 30%.

Higher in durability as compare to PtRu/C.

Maximum current density observed 40% higher than PtRu/C.

Highly CO tolerance.

[74]

PtNi

4.4 nm

Impregnation

[MOR]: Current density observed for PtNi/C catalyst is 5.3 times higher than commercial Pt20/C E-TEK.

Charge transfer during MOR is facilitated for mixed oxides from the non-noble metal.

[55]

PtNi

2–3 nm

Polyol reduction

[MOR]: Heat treatment leads to segregation of Pt particles. Thus, lower MOR activity.

Highest activity was found for a Pt to Ni atomic ratio of 3:1.

Highly stable catalyst with addition of Ni. Mass specific activity over 200 potential cycles.

[77]

PtCo

2.4 nm

Chemical reduction

[MOR]: XPS analysis revealed the strong charge transfer interaction between Pt and Co atoms gives much higher electrocatalytic activity, stability and CO tolerance.

[64]

PtCo

2–5 nm

Chemical reduction

[MOR]: highest catalytic activity achieved by PtC ratio of 9:1.

Exhibited three times power density as compared to commercial Pt/C catalyst.

Efficient in methanol oxidation and CO adsorption on active Pt sites can be explained by bifunctional mechanism.

[51]

PtFe

0.7 nm

Chemical reduction

A higher Pt dispersion attributed to the temperature of chemical reduction route.

[52]

PtZn

3–5 nm

Microwave-assisted polyol

Stable electrochemical activity in acid medium and MOR

Good Co tolerance and long-term durability.

The higher performance attributed to the bifunctional mechanism of the binary catalysts: addition of Zn promotes the center for the generation of Zn–OH species, and more Pt sites are thus available for MOR.

[67]

PtRuSn

50 nm

Thermal decomposition

[MOR]: addition of Sn and Ru to the Pt increases the activity as described by bimetallic mechanism of bifunctional mechanism and electronic properties of Pt by contributing d-electron density in an electronic model.

[68]

PtRuNi

2.5–3.5 nm

Reduction

[MOR]: MOR for PtRuNi (1.98 mA/Cm²) was much as compared to PtRu (1.39 mA/cm²) and pure Pt (0.03 mA/cm²).

[69]

PtRuMo

2.06 nm

[DMFC]: ECSA = 138 m² g⁻¹_Pt, mass activity = 15 A cm² g⁻¹_Pt

[70]

PtNiCr

ND

Reduction

[MOR]: enhance in catalytic activity is attributed to the conditioning process caused dissolution and an oxidation state change of metallic Ni and Cr₂O₃ in the binary catalysts.

The higher MOR of the ternary catalysts compared to the binary alloy was attributed to co-alloying of Ni and Cr, leads to expose more Pt surface sites without reducing specific activities of the catalysts.

The binary and ternary catalysts result from both the well-known bifunctional mechanism and an electronic (ligand) effect.

[78]

PtRuOsIr

5–7 nm

Complex sol gel

[MOR]: composition of alloys: Pt-41 at.%Ru-10 at.%Os-

5 at.%

Ir possess good chemical homogeneity and exhibited excellent catalytic activities.

[79]

PtRuIrSn

ND

Reduction

[MOR]: 25–35% Ir and 10% Sn content revealed high stability of catalyst, and higher in MOR activity than the commercially available E-TEK anode (80%[0.5Pt 0.5Ru]/C.

Ir used is more than other co-alloy because it has higher stability than Pt and Ru. This composition can maintain high catalytic activity with low loading of Pt.

[81]

Pt/α-MoC

ND

temperature-programmed carburization (TPC)

α-MoC provides highly active sites for water dissociation.

Produced abundant surface hydroxyl groups

Methanol could be effectively activated (the effective barrier is 0.79 eV), water dissociation and the substantial reforming of CO cannot proceed at low temperatures (effective barrier of 1.18 eV).

Well-dispersed Pt maximizes the exposed active interface of Pt1/α-MoC and effectively increases the density of active sites.

[82]