Facebook, the fast-growing social network, has moved to shore up its management team by appointing Sheryl Sandberg, Google’s vice-president of online sales, as its chief operating officer.

The move comes as Facebook is under pressure to deliver revenues that can justify the $15bn valuation it drew in a recent investment round. It is further sign that Mark Zuckerberg, Facebook’s 23-year-old founder and chief executive, intends to remain at the helm as it attempts to establish itself as a leading internet company in the same league as bigger rivals such as Yahoo and Google.