  The 2.5-generation (2.5G) ground-based gravitational wave (GW) detectors LIGO
Voyager and NEMO are expected to be operational in the late 2020s and early
2030s. In this work, we explore the potential of GW standard sirens observed by
the 2.5G GW detectors in measuring cosmological parameters, especially for the
Hubble constant. Using GWs to measure cosmological parameters is inherently
challenging, especially for 2.5G detectors, given their limited capability,
which results in weaker constraints on cosmological parameters from the
detected standard sirens. However, the measurement of the Hubble constant using
standard siren observations from Voyager and NEMO is still promising. For
example, using bright sirens from Voyager and NEMO can measure the Hubble
constant with an accuracy of about $2\%$ and $6\%$ respectively, and using the
Voyager-NEMO network can improve the accuracy to about $1.6\%$. Moreover,
bright sirens can be used to break the degeneracy of cosmological parameters
generated by CMB data, and to a certain extent, 2.5G detectors can also play a
role in this aspect. Observations of dark sirens by 2.5G detectors can achieve
relatively good results in measuring the Hubble constant, with an accuracy of
within $2\%$, and if combining observations of bright and dark sirens, the
accuracy of the Hubble constant measurement can reach about $1.3\%$. Finally,
we also discussed the impact of the uncertainty in the binary neutron star
merger rate on the estimation of cosmological parameters. We conclude that the
magnificent prospect for solving the Hubble tension is worth expecting in the
era of the 2.5G ground-based GW detectors.
