They aren't closely associated with either side. If Israel attacked the peacekeepers it would be an act of war, against a far superior opponent. And China would take responsibility for ensuring that the Gazans did not attack Israel. Neither side would be happy, but they'd both have means and incentive to maintain a ceasefire.

It wouldn't be an open-ended commitment. They'd plan a transition. The US has a history of botching such transitions, but China often has a different take on things. Perhaps they'd be more successful. And it would put them in a good position to broker a two-state solution.

That seems more productive than just claiming to support negotiations.